Skip to main content

Full text of "Journal of the Society of Motion Picture Engineers"

See other formats

From the collection of the 

o Prelinger 


San Francisco, California 


Vol 48 JANUARY 1947 No. 1 



Recent Developments in the Field of Magnetic Record- 
ing S. J. BEGUN 1 

Magnetic Sound for Motion Pictures M. CAMRAS 14 

A Magnetic Sound Recorder of Advanced Design 


Magnetic Sound Recording on Coated Paper Tape 

H. A. HOWELL 36 

Research Council Basic Sound Committee: Discussion 
of Magnetic Recording 50 

Magnetic Recording for Motion Picture Studios 

W. C. MILLER 57 

Achievements of the SMPE for 1946 D. E. HYNDMAN 63 

Citation on the Work of Ralph H. Talbot 

E. K. CARVER 65 

The ASA Sectional Committee on Motion Pictures, Z22 

C. R. KEITH 67 

The Determining Role of Research in the Future of 
the Motion Picture B. PRICE 70 

Screen Illumination with Carbon Arc Motion Picture 
Projection Systems 

Current Literature 82 

Society Announcements 83 

61st Semiannual Convention 85 

Copyrighted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 






(Board Under Organization) 
** President: LOREN L. RYDER, 

5451 Marathon St., Hollywood 38. 
** 'Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
** Executive Vice-P resident: EARL I. SPONABLE, 

460 West 54th St., New York 19. 
^Engineering Vice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial Vice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
* Financial Vice-P resident: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
*Treasurer: E. A. BERTRAM, 

850 Tenth Ave., New York 19. 

**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 5451 Marathon St., Hollywood 38. 
*fjAMES FRANK, JR., 356 West 44th St., New York 18. 

*JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*JA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
*WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

"Term expires December 31, 1947. tChairman, Atlantic Coast Section 
**Term expires December 31, 1948. tChairman, Midwest Section. 
Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 

their annual membership dues; single copies, $1.25. Order from the Society at address above. 

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 
General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 
Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., 
Under the Act of March 3, 1879. 


Vol 48 JANUARY 1947 No. 1 



S. J. BEGUN** 

Summary. New magnetic recording media have been developed during recent 
years which will widen substantially the field of application for magnetic recording 
equipment. Probably most outstanding among the new recording media is the non- 
ferrous wire or tape, plated with a thin layer of nickel-cobalt alloy, and the paper 
disks and tapes coated with a dispersion of magnetic powder. 

It might be of particular interest to the motion picture industry that the coated 
recording media can be perforated to obtain synchronization between picture and 
sound. It is also possible to apply the magnetic coating directly to the film base. 

When Valdemar Poulsen, in 1898, built the first magnetic record- 
ing instrument, he named it the "Telegraphone," a name which has 
since been used to identify all types of magnetic recording equipment. 

In the January 1917 issue of the magazine Machinery an article ap- 
peared under the title "The Telegraphone." In the light of recent 
developments, one paragraph of this article merits special attention : 

"Another application which is being developed is the use of the telegraphone 
in connection with the motion picture machine. The talking picture has never 
been made a success because of the difficulty of obtaining perfect synchronism be- 
tween the pictures thrown on the screen and the recording of the voice. With 
the telegraphone, perfect synchronism is possible. This is accomplished by de- 
positing a strip of pulverized iron filings directly on the film itself. The sound 
waves are thus carried directly on the same film as the pictures. In reproducing, 
an amplifier can be located behind the curtain and connected telephonically with 
the motion picture machine." 

It was optical recording which was accepted later as the proper 
method for providing a sound track on motion picture film, but in 
other respects the statement which was made 30 years ago has cer- 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
* * Brush Development Company, Cleveland, Ohio. 


Vol 48, No. 1 

tamly a prophetic note. It is only now that recording media are 
available which use a coating of finely dispersed magnetic powder ap- 
plied to a plastic or paper base. 

It was in 1928 that Pfleumer, in Germany, made the first practical 
attempt to apply a magnetic coating to paper or plastic material for 
use as a recording medium. The A. E.G., in Germany, took over the 
Pfleumer patent and developed in co-operation with I. G. Farben a 
coated recording medium and recording equipment which was 
marketed in 1935 under the name of "Magnetophone." The Magneto- 

FIG. l. 

phone equipment, manufactured even as late as 1939, had a poor 
signal-to-noise ratio (about 20 db), but the instrument served quite 
adequately as a dictating machine. During the war the Germans 
made considerable further progress in developing recording media 
of this type, but information about these improved media became 
available only lately. 

In this country little attention had been given to the development 
of coated magnetic recording media until, in 1939, the Brush Develop- 
ment Company started experimental work in this field. This activity 
was greatly accelerated during the war since it became clear that such 


coated recording media would be relatively inexpensive to manu- 
facture. This war development, which was conducted under the 
auspices of the National Defense Research Committee, seems to be 
one of the most potent factors which will bring magnetic recording 
from the scientific backstage into the commercial forefront. 

Only about ten years ago it was considered necessary to have the 
recording medium move with a speed of two to three feet per second, 
to cover a frequency band wide enough for low, or possibly, medium 

FIG. 2. The BK-401 magnetic paper tape recorder. 

quality sound recording. With the coated recording materials it is 
now possible to go up to about 5000 cycles with a speed as low as 
7.5 in. per sec. In Fig. 1, the frequency response of a so-called paper 
tape recorder is shown, in which the recording medium moves at 
7. 5 in. per sec. 

The recorder itself, which was designed for home use, is shown in 
Fig. 2. The design is of some interest to the motion picture engineer, 
since its mechanical arrangement is very similar to that of a motion 
picture film projector. It uses two 8-mm reels with a 7 in. diameter. 

4 S. J. BEGUN Vol 48, No. 1 

To simplify the mechanism, three motors are used. The shafts of 
two motors serve also as reel shafts. The third motor drives through 
a simple mechanical filter a capstan which propels the tape with a 
linear speed of 7.5 in. per sec. 

In Fig. 3 a top view of the unit is shown, with the tape moving from 
one reel through the magnetic head over the capstan drive to the other 

Depending upon the direction of the tape motion, either one or the 
other reel motor is energized. For fast forward and fast rewind, the 
tape is removed from the capstan. Half an hour of recording can be 
stored on a 7 in. reel and can be rewound within less than one minute. 

FIG. 3. Top view of the BK-401 magnetic tape recorder. 

Fig. 4 shows the capstan drive and its mechanical filter arrange- 
ment. The motor shaft drives the capstan flywheel through a rubber- 
tired idler. 

Magnetically coated recording media, when used with the proper 
recording and reproducing heads, not only have an excellent frequency 
response characteristic when considering the slow operating speed 
of the medium, but they also have a remarkable dynamic range. 
Under carefully controlled experimental conditions, a signal-to-noise 
ratio of better than 60 db has been measured and, in fact, no final 


data are at present available on what signal-to-noise ratio could be 
obtained under ideal conditions. The major difficulty which con- 
fronts the experimenter is the low output level on the terminals of the 
reproducing head, which in many cases makes the amplifier noise the 
limiting factor. To obtain such a dynamic range, it is necessary to 
have powder particles of extremely uniform size. Furthermore, these 
particles must be of small diameter, not exceeding one micron. In 
Fig. 5 an electron-microscopic picture of the powder particles is 

The level of reproduction depends upon the thickness of coating 
upon the concentration in the coating and upon the magnetic proper 

FIG. 4. Capstan drive and mechanical filter of the BK- 
401 magnetic paper tape recorder. 

ties of the powder particles. Unfortunately, the pigment concentra- 
tion in the coating cannot be increased beyond a certain limit without 
interfering with the making of a good dispersion. To secure good 
frequency response the thickness of the coating must not substantially 
exceed 0.6 mil. Powdered materials with better magnetic character- 
istics are under development. 

There is also the possibility of obtaining a higher output level by 
making the tape wider but then one is confronted with difficulties of 
mechanical nature. With a speed of 7.5 in. per sec., the wavelength 
of a recorded 5000 cycle signal is only 1 .5 mils. If the position of the 
gap of the magnetic recording head with respect to the sound track 

6 S. J. BEGUN Vol 48, No. 1 

on the recording medium deviates ever so slightly from the position 
of the magnetic gap of the playback head, the level of reproduction 
for high frequencies will drop substantially. This is a problem with 
which the sound motion picture engineer is quite familiar. It is, in 
many respects, similar to the results which one obtains when one re- 
produces a variable density recording with a slightly shifted light slit. 
To obtain an essentially flat frequency response up to 5000 cps, 
with a recording medium moving at a speed of 7.5 in. per sec, extreme 
care must be taken in the design and construction of the recording 
and reproducing heads. These magnetic heads are formed of two 


. * 

FIG. 5. Electron micrograph of magnetic powder 

identical pole pieces, assembled so that their ends are separated by 
extremely small gaps, which should not exceed 0.0005 in. This small 
gap is required during the recording process in order to focus the mag- 
netic flux in almost a geometric line perpendicular to the motion of the 
recording medium; and it is also required in reproduction, since the 
output level drops substantially when the gap length approaches the 
dimension of a recorded wavelength. 

In Figs. 6 and 7, two different types of recording heads are shown. 
In the first recording head, the pole pieces consist of a number of 
stacked laminations. In the other head each pole piece is formed of a 

Jan. 1947 


single sheet-metal portion, bent to proper shape. In botji heads the 
pole pieces are symmetric with respect to the gaps. A coil is placed 
on each pole piece. This symmetry reduces substantially the effect 
of external magnetic flux disturbances, and yet maintains high effi- 

FIG. 6. Laminated recording head. 

FIG. 7. Single sheet-metal recording head. 

ciency in picking up the magnetic signal from the recording medium. 
The head which employs pole pieces made of a single piece of sheet 
material is more susceptible to permanent magnetic fields and should 



Vol 48, No. 1 

not be used where strong magnetic fields could permanently magne- 
tize it. The laminated head has higher losses but cannot as easily 
be permanently magnetized. 

In the completed state, each of these heads is preferably provided 
with magnetic shields. As the output level is low at low frequencies, 
the addition of the shield is very important, since the hum bucking 
feature in itself would not be effective enough to give a good signal-to- 
noise ratio at low frequencies. 

As do motion picture films, magnetically coated paper or plastic 
tapes vary in length as the result of temperature and humidity. If 
it is desired to synchronize a picture with sound, special provisions 
have to be made. The use of perforations in the magnetically coated 
tapes provides one well-established method. In a typical motion 





250 500 1000 2500 


5000 10,000 

FIG. 8. Unequalized frequency response of paper tape at 
18 in. per sec; recorded at 0.3 ma, max current = 0.8 ma, bias 
1.7 ma at 30 kc. 

picture sound recorder, a 35-mm magnetically coated perforated tape 
can be substituted for the 35-mm light-sensitive film, and the light 
valve can be replaced by a magnetic recording head. If desired, a 
number of sound and signal channels can be recorded simultaneously. 
Electronic methods to obtain synchronism as an alternative to the 
use of sprocket holes are under consideration at present and might 
lead to a practical system. 

The coating can be applied to the film base directly. A film pro- 
vided with a magnetic sound track might be extremely useful for the 
sound motion picture amateur because of the erase feature. While 


projecting the film, recordings can be made over and over until a 
satisfactory sound arrangement is obtained. 

Fig. 8 shows an unequalized frequency response of a paper tape 
moving with a speed of 18 in. per sec, the same as that of 35-mm 
sound film. It is fairly easy to equalize such a magnetic recording 
system up to 13,000 cps, which is certainly comparable to the best 
which has been done in film recording. 

Up to this time it has been considered impossible to obtain any 
worthwhile sound recording on 8-mm film. The speed of 8-mm 
film, assuming 24 frames per sec, is a little better than 3.5 in. With 
magnetic recording a quality can be obtained which is good enough 
for speech intelligibility and it 
appears that for amateur applica- 
tions 8-mm sound film is now in 
the realm of possibility. 

Of course, if a magnetic record- 
ing track is provided on 16-mm 
film, the quality of reproduction 
is certainly adequate for amateur 
use and most likely even for pro- 
fessional applications. 

Because of the low speed of 
the recording medium, it has for 
the first time become possible to 
design a practical magnetic disk 

recorder. The idea of recording FlG - 9 - Disk-type magnetic paper 

on magnetic disks is certainly not 

new. In a newspaper article (Springfield Republican, Sept. 15, 1912), 
the following statement was made : 

"By substituting small steel disks for the customary steel wire, it is plain that 
records may be taken by magnetic impression as they are now taken mechanically 
on the wax disks of a phonograph. The disks can then be sent by mail as letters, 
with no danger that anyone can read them except the one for whom they are 
meant, for the blank steel tells no tales till it is put on another Telegraphone and 
repeats the message it conceals." 

When these words were written, the field of magnetic recording was 
yet in its infancy and it would have been entirely impossible to design 
equipment of any commercial value. But because of the development 
of the magnetically coated recording media, what used to be a dream 
has now become reality. 



Vol 48, No. 1 

In Fig. 9 a disk-type recorder is shown. A three -minute voice re- 
cording can be made on a coated paper disk, starting from an inner 

W (B) 

FIG. 10. A Cross section of plated wire; B Cross 
section of plated tape. 

diameter of 5.5 in. to an outer diameter of 8.5 in. The sound track 
is 14 mils wide and the spacing between sound tracks is 1 1 mils, thus 

FIG. 11. Representative hysteresis loops of various re- 
cording media. 

allowing for 40 tracks per in. The turntable rotates at only 20 rpm. 
To guide the pickup properly along the helical sound track a grooved 


guide disk is placed on the center of the record and is, by an appro- 
priate pin, brought into a definite relationship with the record. 

During the war the Brush Development Company, under the aus- 
pices of the National Defense Research Committee, developed an- 
other new recording medium which also will have its place in the 
magnetic recording field. A ductile nonmagnetic nonferrous wire, 
such as a brass wire, is used as a base material on which a thin layer 
of a highly magnetic nickel-cobalt alloy is plated. 

To draw a material which has uniform magnetic characteristics 
with a high coercive force and a reasonable remanence is a fairly ex- 

; p; 


k ^i. 



FIG. 12. 

pensive process. It is true enough that substantial gains have 
been made in producing better solid magnetic recording media, 
such as wire and tape. However, the basic idea underlying the use 
of the plated recording medium was that it would be possible, with 
little expense, to draw a fine brass wire with high dimensional accu- 
racy and then plate this wire inexpensively to secure a magnetic alloy 
deposition of excellent dimensional and magnetic uniformity. In 
Fig. 10 the cross section of such a plated wire is shown. Fig. 1 1 shows 
the hysteresis loops of carbon steel wire, which was used in the 1930's; 
the stainless steel wire, which was used particularly in military equip- 

12 S. J. BEGUN Vol 48, No. 1 

ment during the war; and the plated wire which now will become 
available on commercial wire recording equipment. 

In Fig. 12 the frequency response of a Brush BK-303 wire recorder 
is shown, in which the plated wire moves with a speed of 2 ft per sec. 

The question might be raised, "Why should wire be used at all in 
the future, since from all available indications the coated magnetic 
recording materials seem to have so many advantages ?" The answer 
is fairly simple. Though the coated materials can be operated with 
slower speed than the solid or plated wires or tapes to obtain an 
equivalent frequency band, the tapes have a substantially bigger 
cross section, and thus more space is required to accommodate them. 
Particularly for applications where a long playing time is needed, 
wire recording, probably in preference to any other method of re- 
cording, will have its place. 


MR. R. J. TINKHAM: I wanted to ask what coercivity can be obtained with 
these plated materials. 

DR. BEGUN: The coercivity of the plated wire as produced commercially is 
between 200 and 220 oersteds. It has been found possible to plate material with 
a coercivity as high as 300 oersteds. 

MR. A. SHAPIRO : What linear speed per minute was the tape running through 
the machine during the demonstration? 

DR. BEGUN: There were two magnetic paper tape recorders demonstrated; 
one model, which soon will be available on the market as a home recorder, has a 
paper tape speed of 7.5 in. per sec. The tape of the other unit moves with a 
speed of 18 in. per sec., a speed equal to that of 35-mm film. 

DR. J. G. FRAYNE: What is the order of the distortion that is possible? What 
is the minimum distortion that can be obtained under well controlled conditions 
in either of these types of machines? 

DR. BEGUN: Unfortunately, there is still not sufficient information available 
to supply data on distortions.. From the experiments we have made to date, it 
seems that for a dynamic range of 40 db, the intermodulation product does not 
exceed 5 per cent. 

MR. L. HOLMES: There has been a lot of discussion about signal-to-noise ratio 
and signal-to-noise measurements on magnetic recording. We have heard some 
claims of 80 db for the captured German equipment. I would like to ask if Dr. 
Begun could explain how the signal-to-noise measurement of 60 db was measured, 
whether it is for the medium alone, or whether it is the medium plus equipment, 
whether it has any pre-equalization or post-equalization. 

DR. BEGUN: Unfortunately, the Chairman has limited the time of discussion 
so that I am not able to go into all the details of how signal-to-noise ratio has been 
measured. However, I would like to summarize briefly the arbitary test proce- 
dure which was followed: 

First, a curve is plotted which relates the input current to the recording head 


for a 1000-cycle tone to the output voltage. The system is considered to have a 
linear transfer characteristic as long as a current increase in recording results in a 
proportional voltage increase in reproduction. The point where the output 
voltage deviates more than one decibel from the linear input-output relationship 
is designated as overload point. The ratio of the overload voltage to the noise 
voltage (distributed over the complete frequency range) is considered the signal- 
to-noise ratio. In the measurements referred to in my presentation, special care 
had to be taken in selecting the first tubes. 



Summary. A magnetic sound track on motion picture film is convenient and 
economical. The final recording can be monitored -while it is being made and requires 
no processing. All or part of the sound track can be erased, and a new record put on; 
or the film can be edited in the usual manner. Apparatus for making high-quality 
records is described, including the sound head, constant speed drive mechanism, 
amplifier equipment, and the magnetic track. Over-all performance, frequency re- 
sponse, dynamic range, and distortion are given. 

Three fundamentally different sound recording methods can be 
used with motion pictures. For a long time the mechanically cut or 
embossed recording was the most highly developed, and the first 
talkies used a phonograph disk synchronized with the picture. An 
optical sound track, however, is so satisfactory for most sound on 
film work that it is now used almost exclusively. Magnetic recording 
apparently has been neglected, although it has some unusual ad- 
vantages over the conventional systems. 

Fig. 1 illustrates the three sound recording methods. Similarities 
between the optical and the magnetic methods suggest that they may 
be used interchangeably, provided certain mechanical and electrical 
modifications are made. To compare the two systems we might list 
some advantages and disadvantages of each : 

Optical Recording Advantages 

(1) Better resolution better high-frequency response at a given speed; 

(2} No direct contact of recording head with the film no wear or clogging 

(5) Ease of duplication direct contact printing. 

Optical Recording Disadvantages 

(1) Requires developing before record can be played back; 
(2} Relatively expensive; 
(5) Cannot be monitored immediately ; 

(4) Film technique must be handled in the dark expiration dates proc- 
essing skill required. 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
* * Armour Research Foundation, Chicago, 111. 



Magnetic Recording Advantages 

(1) Simplicity; 

(2) Low cost of the magnetic system ; 
(5) Immediate monitoring if desired ; 

(4) No processing; 

(5) Magnetic record medium can be erased by demagnetizing and used over 
again (economy of material) ; 

(6) Parts of sound track can be edited by erasing, and dubbing in new sound ; 

(7) No serious distortion with overmodulation. 

Magnetic Recording Disadvantages 

(1) Head contacts the record possibility of wear; 

(2) Technical performance not 
quite equal to the best pos- 
sible with advanced optical 




It should be pointed out that 
the above lists are based on the 
present state of the art. In 
the last decade work done 
with film recording has been 
outstanding, especially with 
the advent of fine grain films 
and ultraviolet optics. It ap- 
pears that film recording tech- 
niques have approached closely 
to theoretical limits of perfec- 
tion, and there is no reason to 
expect revolutionary changes 
in the near future. On the 
other hand, we have by no 
means reached the ultimate in 
magnetic recording heads or media. Theoretically a magnetic track 
can be at least as good as an optical one, and the magnetic record 
should give a greater dynamic range without resorting to artificial 
noise reduction schemes. 

Mechanical Drive. In constructing a recording machine for 
studio work, 35-mm equipment was chosen because excellent wow- 
free, rigidly built film machines are available. These can be con- 
verted to magnetic recorders with a minimum of trouble . A sound-on- 
film recording machine built up from standard equipment is shown in 


FIG. 1. 

Sound recording methods for 
motion pictures. 



Vol 48, No. l 

Fig. 2. The magnetic film, stored on the upper reel, is pulled into 
the sound head by sprockets of an old Simplex projector from which 
the intermittent mechanism was removed. The sound head is the 
latest Motiograph type. From this the exciter lamp, photocell, and 
optical systems were removed. In their place was mounted a plate 
containing three magnetic heads as shown in Fig. 3. These heads 
contact the film while it is against a rotary-stabilized drum. The 
film then feeds over a sprocket and on to a take-up reel in the conven- 
tional manner. 

Magnetic Heads. The magnetic head assembly is illustrated in 

Fig. 4. A rigidly mounted 
adjustable plate holds three 
heads. Each head has an in- 
dividual arm, spring biased 
against the film while the 
latter rides against the stabil- 
ized brass drum. The upper 
head is for erasing; it clears 
the magnetic track from any 
previous record and prepares 
it for receiving a new record. 
The erase coil is fed with high- 
frequency energy at 40 kc. 
Although a half ampere of 
current is sufficient for de- 
magnetization, approximately 
one ampere is used to ensure 
perfect cleaning. 

Recording is accomplished 
by the center head, which 

contains a main audio winding and an auxiliary high-frequency 
coil. The auxiliary coil is connected in series with the erase coil to 
secure proper high-frequency excitation. The audio winding is ener- 
gized with signal current from the audio amplifier. 

Below the recording head, and spaced from it, is the monitor or 
playback head. This is surrounded by a mu-metal shield to isolate it 
from direct pickup of magnetic flux from the recording head. The 
pickup head feeds through an amplifier, and reproduces the sound 
which has been recorded on the film 50 milliseconds before. It is 
thus possible to monitor the record as it is being made. Distortion, 

FIG. 2. Magnetic film recorder. 

Jan. 1947 



etc., caused by improper adjustment is detected immediately, and 
steps can be taken to correct any faults without delay. 

For best results it has been found advantageous to use "graded" 
sizes of magnetic heads. As seen in Fig. 5 the erase head is 0.240 

FIG. 3. Close-up of sound head. 







Fig. 4. Magnetic head assembly. 

in. wide ; it clears a track almost Vie in. wider than the pickup channel 
space needed. The recording head is 0.200 in. wide. The pickup 
head is made 0.187 in. wide, and does not cover the entire recorded 
track. With an arrangement such as this, slight errors in lateral 
alignment are not serious, and do not result in distortion or cross talk. 
Magnetic Film. The recording film itself is a new product of 



Vol 48, No. 1 


special interest. A cross section through a piece of 35-mm mag- 
netic film is shown in Fig. 6. Standard acetate or nitrate stock is 
used for base material. Instead of the usual emulsion (or in addition 

to it) a half-mil coating of spe- 
cial magnetic material is used. 
The magnetic material is very 
finely divided, having a particle 
size of one micron or less, dis- 
persed in a binder which gives a 
good bond to the base material. 
Approximate magnetic proper- 
ties of the coating in its final 
form are: 



Coercive force H c = 350 

Residual magnetization B r = 500 
Maximum field for 

above readings B m = 1,000 



It is noteworthy that high mag- 
netic properties can be attained 
with peak fields as low as 500 or 
700. This means that the ma- 
terial not only can be magnetized 
easily but also can be erased 
readily. Complete erasing by 
the high-frequency method has 
always been difficult with previ- 
ous high-coercive materials be- 
cause of the high saturation fields 
required. As has been noted in 
previous work 1 a high B T contrib- 
utes to low frequency output, 
while a high H c gives good high 
frequency response. Also a high 
H c ensures that the record will 
be less influenced by stray mag- 
netic fields which could cause 

deterioration, especially of the high frequencies. 

Dimensions of the sound tracks are given in Fig. 7. The useful 

working space on a 35-mm film coated all the way across is approxi- 


FIG. 5. Magnetic head dimensions. 

Jan. 1947 



mately an inch. Four sound tracks, each 3 /ie in. wide and spaced Vw 
in. apart can be accommodated. Ordinarily, only one channel is 


v v 

i i 


A A 

\ / 



.005 IN. THICK .0005 IN. THICK 
i t 

i i ' i I 

FIG. 6. Thirty-five millimeter magnetic 
recording film. 



.050 .050 


FIG. 7. Four-channel 35-mm sound system. 

used, but the availability of the other channels offers some interest- 
ing possibilities : 

(1) Microphones might be placed in several positions, each pickup recorded 



Vol 48, No. l 

on its own channel, and the best "take" chosen. This might be important for 
new events where everything must be right the first time. 

(2} Binaural or Stereophonic recordings are possible. 

(5) One or more tracks can be used for control purposes. 

(4) In editing, background music, sound effects, and control signals can be 
put on the side tracks. These can be erased, changed, or rearranged as many 
times as needed. When a satisfactory composition is made, all of the tracks are 
blended together in the rerecording process. By this process, the main record is 
rerecorded only once, thus minimizing noise and distortion. 

(5) For some types of work the film spools can be interchanged and the film 
can be run through again, thus eliminating rewinding, and doubling the recording 
time without the need for extra heads or other apparatus. A binaural system 
has been made in which channels 1 and 3 are used with the film running in one 






FIG. 8. Magnetic films and tapes. 

direction; and channels 2 and 4 are picked up when the film is run in the reverse 

(6) By using narrower tracks, eight, sixteen, and even more channels can be 
accommodated. The quality is of course sacrificed when very narrow tracks are 

Experiments have been made also with a wide variety of bases 
carrying a magnetizable material. Some of these are illustrated in 
Fig. 8. Excellent results have been obtained with a magnetic sound 
track on 16-mm picture film, and a paper describing this work is now 
in preparation. An 8-mm sound system shows promise ; although the 
quality is poor, it may be adequate for amateur work. 

Jan. 1947 



Amplifier Equipment. The amplifier equipment needed for 
magnetic recording is conventional in most respects. Ordinary 


Fig. 9. Recording system. 

sound-on-film amplifiers can be modified readily for magnetic 
sound. Fig. 9 is a block diagram of a typical recording system. Pre- 
equalization is used for the high-frequency end of the spectrum to 


SKC 10 KC 20 KC 


FIG. 10. Response of recording equalizer. 

compensate for slit-loss in the recording head and for the inefficiency 
of short magnets in the record medium. The extent of these losses is 
indicated by the response curve of Fig. 10. Except for the boost at 



Vol 48, No. 1 

high frequencies the recorded flux is proportional to the input voltage 
of the system. This may be expressed by 

where </> r = the recorded flux, 

KI = a constant of proportionality, 
Fi n = the input voltage to be recorded. 






FIG. 11. Playback system. 



FIG. 12. Synchronization of sound and picture cameras. 

In playback, the voltage generated by the head is proportional to 
the rate of change of flux, so that 

(K t a constant). 

Jan. 1947 



This equation indicates that the playback voltage is proportional 
to the derivative of the original signal, which not only causes a phase 
shift, but also gives a rising frequency characteristic. For proper re- 
production an integrating network is necessary. It is advantageous to 
place this integrating network in a later stage of the voltage amplifier 
where it will also reduce tube noise. The playback system is dia- 
grammed in Fig. 1 1 . 

Operation. Magnetic film recorders may be used in the same 
way as optical recorders. A recorder using synchronous motor 
drive is illustrated in Fig. 12. The sound camera and the picture 
camera are brought up to speed, and reference marks for synchroni- 



500 IRC 


FIG. 13. Over-all frequency response of 35-mm magnetic 
recording system. 

zation made by clapping boards together in the usual manner. The 
recorded noise is as sharply defined on the magnetic track as it is on an 
optical one ; naturally it cannot be seen, but it can be located easily 
by exploring with a pickup head in the editing machine. 

A synchronizing system as in Fig. 12 may be convenient. Here a 
pair of relays are mounted, one in the motion picture camera, the 
other in the sound camera. Energizing these relays puts a scratch 
or a dab of paint on each of the films. These marks are later used for 
synchronization or for reference. Since the magnetic film is driven 
at a standard speed of 90 ft per min, it will fit directly into editing, 



Vol 48, No. l 

rerecording, and printing machines, these being provided with mag- 
netic pickup heads. 

Over-all response of the experimental system is given in Fig. 13. 
The frequency characteristic is flat from 50 to 12,000 cycles within 
=*=3 db. Intermediation distortion was measured by recording a 
combined 100-cycle and 7000-cycle signal, the 7000-cycle component 
being 12 db below the 100-cycle tone. Wave analyzer measurements 
showed a total intermodulation distortion of 4 per cent at normal 
recording levels. Variation of intermodulation distortion with re- 
cording level is given in Fig. 14. Dynamic range measurements indi- 
cate that a maximum signal-to-noise ratio of about 45 db is attained 

Conclusions. A 35-mm magnetic sound recorder has been de- 
veloped which has a number of novel and desirable features for 




% 6 

FIG. 14. 


Intermodulation distortion versus recording 

motion picture work. The system can be used as an alternative to 
present photographic methods, and should be more flexible and 
economical. Laboratory measurements indicate that further im- 
provements are probable. 

The writer wishes to thank R. T. Van Niman and the Motiograph 
Company for their help in setting up the sound head. Acknowledg- 
ment is also due R. E. Lewis of Armour Research Foundation for his 
valuable help and consultation. 


1 CAMRAS, M.: "Theoretical Response from a Magnetic Wire Record." 
Proc. LR.E. and Waves and Electrons, 34, 8 (Aug. 1946), p. 597. 



MR. R. C. HOLSLAG: Is the magnetized track transparent or opaque? 

MR. CAMRAS: The magnetized track is opaque. I do not know of any trans- 
parent material that is available. 

MR. J. I. CRABTREE: I would like to ask two questions: How long does the 
magnetism last? Second, in the case of the paper record, how many feet are 
on a reel? 

MR. CAMRAS: As far as we know, the record life would be determined by the 
base on which it is put, rather than by the magnetic material. The records are 
quite permanent with respect to time and with respect to repeated playbacks. 
They can be run thousands of times. In fact, experimental records have been 
played back hundreds of thousands of times, and I think the deterioration was 
in the order of 5 or 6 db. 

In our film records, of course, the amount of film is exactly the same as for op- 
tical recording. A paper record has about 1000 ft of paper per reel of about 7 in. 
in diameter. At a speed of 7 or 8 in. per sec, it will last for half an hour. 

MR. CRABTREE: How complete is the wipe-off? 

MR. CAMRAS: The erasing is perfectly complete because the material is de- 
magnetized, provided the peak erase field is considerably greater than the peak 
recording fields used. 

MR. GEORGE LEWIN: In the use of this method, is the track put on before or 
after the picture is developed? 

MR. CAMRAS: It can be put on either way. With existing pictures, sound 
can be added by a coating process. The film we have here had the track put on 
after. The possibility of adding a sound track to films which are already on 
hand is attractive. On the other hand, the track is quite waterproof, and we 
have made tests to see if it would stand the normal developing solutions. We 
can make a magnetic sound track directly as we make the picture, and the track 
will go through all the film processing and be retained. 

MR. LEWIN: If you want to release this in theaters, each individual print 
will have to be recorded . 

MR. CAMRAS: Of course, each release has to be run through a printer anyway. 
In that printer the magnetic track could be picked up and rerecorded . 

MR. CRABTREE: Is there any offsetting of the magnetized record onto another 
convulsion of film? In other words, does the record on the paper or film offset a 
magnetic image onto the portions of the tape adjacent to it on the reel? 

MR. CAMRAS: Yes, we call that effect "transfer." There is no appreciable 
transfer with anything that is spaced by the thickness of the film which is about 
6 mils or so. There is some transfer effect in wire recording where the convolu- 
tions of wire are in direct contact with each other, but even those can be kept in 
the order of 40 db or less, as compared to the recorded signal ; and it is no prob- 
lem at all with film recording. 

DR. J. G. FRAYNE: Are these films available commercially, or are they just 
experimental films made up for your development work? 

MR. CAMRAS: These films were made by Armour Research Foundation 
especially for development work. They are not available yet, but should be in 
the near future. 

MR. BRUNSWICK: Is there any effect from metallic sprockets, and such, in 

26 M. CAMRAS Vol 48, No. 1 

running through ordinary projection equipment? Does that cause any deteriora- 
tion of the magnetic image? 

MR. CAMRAS: It will not if the material is not in direct contact. Is that 
what you mean? 

MR. BRUNSWICK: In other words, if it ran through ordinary projection equip- 
ment repeatedly? 

MR. CAMRAS: The only modification we made was to take off the hardened 
stabilizer roller which became magnetized, and to substitute a brass roller. We 
have not put any hard surface on the brass roller, but it could be chrome-plated. 
That is the only change we have made. Otherwise the equipment is standard. 

MR. WALTER SILVERS: If you have a can of film and drop it, will that demagne- 
tize and erase the image? 

MR. CAMRAS: No, it will not affect the recording at all. 

MR. CRABTREE: In your 16-mm demonstration there was a ground noise on 
this side of the room. 

MR. CAMRAS: I think you will notice the noise persisted even after the film 
had run off the head. This "vibrator hash" is caused by contact points on the 
motor governor. Otherwise the noise level should not be much worse than 
what you heard on our 35-mm equipment. 

MR. E. W. KELLOGG: There has been reported in plenty of tests the fact that 
a very satisfactory magnetic rerecording on coated paper, narrow strip, works 
out very well. But, personally, I would anticipate some mechanical trouble in 
putting it on anything that is as stiff as motion picture film. I would expect 
you would have a kind of self -aligning mounting of your recording and playback 
head. Is that correct? 

MR. CAMRAS: That is right. It seeks its own position. 

MR. C. A. LINDSTROM: You mentioned ground noise. What in magnetic re- 
cording would cause a ground noise at all? 

MR. CAMRAS: There is noise in every recording system that has so far been 
used. Of course, we try to keep it at a minimum. I think the noise would de- 
pend upon the particle size of the material, when you get irregularities which 
approach the gap size in order of magnitude. That would correspond to grain 
noise in a photographic recording. 

MR. C. R. SKINNER: What is the relative output of this system? Is it less 
sensitive than optical recording? 

MR. CAMRAS: I do not know what the optical recording systems give, but I 
believe the head plus matching transformer of the 35-mm job gives as much as 
1 / 4 -v peak output to the first grid. 

MR. GEORGE TALLIAN : I would like to ask two questions : First, did you make 
any splices, and what did those splices sound like as they went through? 

MR. CAMRAS: I do not think you heard any splices. They sound just like a 
click. If you have a continuous magnetic coating, then you should have a 
minimum of noise. You can hear a thud, or you can hear a slight click, depend- 
ing on how skillfully the splice is made. I think it would correspond very 
closely to optical systems. 

MR. TALLIAN : The second question is, did you put your magnetic material on 
the emulsion side or the celluloid side of an already developed picture? 

MR. CAMRAS: We have done both. I believe it comes out that in order to re- 


produce the sound on 16-mm film properly, and get the head located on the out- 
side, we have to put the track on the back side of the film, not on the emulsion 
side; which is an advantage, I think, if we have to coat after the film has been 
made. But we have done it both ways, and obtained satisfactory coatings. 

MR. ST ANSEL: Could you give a little more information on the network used 
in the playback? (Fig. 11.) 

MR. CAMRAS: The recorded flux is proportional to the signal. In other words 
if we mapped the flux we would find that it was in direct proportion to the input 
signal. In order to play back, we have to use a magnetic device which is sensi- 
tive not to flux, but to the rate of change of flux. Therefore, if our record was a 
sine wave, we would find that we got a cosine wave on the reproduced signal; 
and also the output would be directly proportional to frequency. When we dif- 
ferentiate a sine wave, we have a frequency term appearing in the coefficient. 

MR. STANSELL: Is that just an RC network? 

MR. CAMRAS: Yes, it can be an RC network. We use a slight modification 
but an RC network can be perfectly satisfactory. 

MR. F. C. SPIELBERGER: I would like to know about the volume range. You 
have said you do not have distortion as in film. Do you have saturation at high 

MR. CAMRAS: Yes, it corresponds to saturation but is much smoother. It 
sounds like an overloaded amplifier rather than the harsh sound of an over- 
modulated galvanometer. 

MR SPIELBERGER: What is the volume range you get without distortion? 

MR. CAMRAS: I think it is in the order of 45 db, if we record at the level corre- 
sponding to 5 db on Fig. 14. I think the 5-db level corresponds to something 
like 5 per cent distortion. 

MR. J. W. THATCHER: Could you tell me at what speed you were running 
those films? 

MR. CAMRAS: The 35-mm film is run at the standard speed of 90 ft per min. 
The 16-mm is run at 24 frames, which comes out to be somewhere between 7 and 
8 in. per sec. 

MR. P. E. BRIGANDI: In studio practice we record a negative and then we make 
prints which we use for editorial purposes, and preserve that negative so it will 
not be scratched or marked. What is your method, using one of these original 
tracks? How do you propose to copy it to use it in editing? 

MR. CAMRAS: If we wanted to copy it, we could copy it magnetically, and re- 
record it on another magnetic track, provided we wanted to use magnetic sys- 
tems all the way. We can use the original film and record or rerecord various 
sound effects and other things on adjacent tracks without in any way affecting 
the original track. And then, when we get the proper music, sound effects, etc., 
at the proper levels, we can rerecord the original track plus all the other tracks 
mixed together, onto an optical track, if we wished a release print to be used in 
conventional projectors. 

MR. BRIGANDI: I was thinking of the earlier steps; as you are editing, you 
want to cut a little bit of the scene and add another piece from another scene to- 
gether. Would you rerecord the track to use in the cutting rooms for that pur- 
pose, to assemble dialogue track, for instance, in continuity? 


MR. CAMRAS: I do not see any alternative except rerecording unless you wish 
to edit the original track as it came. 

MR. BRIGANDI: You mentioned the saving in the studio. We still would have 
to use another transfer for editing purposes. 

MR. CAMRAS: I would say that is so if you wanted to do actual cutting and 
wanted to preserve the original. At any time, though, you can record it onto an 
optical system. You could have a magnetic original and do all your cutting on 
the optical tracks, if you wished. 

MR. LEWIN : You mentioned the 40-kilocycle erasing current as going through 
the recording head as well. 

MR. CAMRAS: The theory of that is rather involved. I believe it has been 
written up in several articles, but in short we need a bias, or you might say an 
exciting current in recording, in addition to the audio signal. This straightens 
out hysteresis effects of the magnetic material, and allows linear recording. 


Summary. Recent developments in magnetic recording have led to practical use 
of this art as a high-fidelity recording system. The particular apparatus described is 
the result of a need for wire recording equipment of professional caliber. It is char- 
acterized by good frequency response, low distortion, freedom from ''wow" and flutter, 
and lock-in synchronous drive. The electrical and electromagnetic portions are the 
result of experience gained by research during the war. The mechanical portions 
have many parallels in motion picture equipment design. This apparatus is suitable 
for many motion picture recording applications. 

Magnetic recording is about 50 years old. The first magnetic sound 
recordings were made by the Danish scientist, Vlademar Poulsen, just 
before the turn of the century. He recorded sound magnetically on 
heavy steel wire, but the reproduction was poor. 

Because greater amounts of acoustical energy were available from 
mechanical recording systems than from magnetic systems, the 
mechanical systems were developed to a very high degree throughout 
the later years. However, with the advent of the vacuum tube and 
certain other techniques, it became possible to make practical mag- 
netic recordings. 

Following Poulsen 's original efforts, work was done in Germany, 
and later in this country by Bell Telephone Laboratories, Brush De- 
velopment Company, and others. Recently Marvin Camras, of the 
Armour Research Foundation, discovered principles and added re- 
finements which have made magnetic recording both practical and 

A professional recorder of any type should incorporate as minimum 
requirements good frequency response, wide signal-to-noise ratio, low 
distortion, ease and economy of operation, and adaptability to exist- 
ing auxiliary equipment. 

Magnetic recording possesses certain advantages not found in other 
types. Among these are its long playing time with compact and light- 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
* * President, f Chief Engineer, Magnecord, Inc., Chicago, 111. 


30 R. J. TlNKHAM AND J. S. BOYERS Vol 48, No. 1 

weight records, and its property of being unaffected by extremes of heat 
and cold. Mechanical shocks and vibrations are no problem during 
either recording or playback. The wire may be reused an unlimited 
number of times simply by erasing the previous material. Instantane- 
ous reproduction is possible because the recording medium requires no 
processing. Repeated playbacks result neither in an appreciable in- 
crease of background noise nor in a noticeable deterioration of the 
recorded material. 

The mechanical design considerations of a wire recorder have much 
in common with those encountered in motion picture equipment, plus 
a few more. It is difficult to grab hold of the wire mechanically. It is 
extremely difficult, if not impossible, to put sprocket holes in a 0.004 
in. diameter wire. This led initially to a spool drive type of machine 
wherein the takeup spool pulled the wire past the recording and play- 
back heads. As the spools were driven at a constant angular velocity, 
the wire traveled faster and faster as more wire was wound on the 
take-up spool. This had obvious disadvantages, the chief one of which 
was the variable frequency response resulting from the variable wire 
speed. Spool driven systems cannot be made to give the smooth wire 
drive demanded in professional type equipment because of the rapid 
instantaneous changes in the spool radius caused by the random piling 
up of the wire across the face of the spool. This gives rise to a random 
type of flutter. 

To overcome these difficulties, it is obvious that the wire should be 
driven and the spools used merely to pay off or take up the wire at the 
necessary rate in the same manner as motion picture film is spooled. 
A capstan drive of some sort is in order. There are three general 
classifications of capstans : multiple wrap, in which the wire is passed 
around the driving member several times; pinch drive, in which the 
wire is held against the driving member by a pressure roller, usually 
rubber; and the jam drive, which has a wedging action on the wire. 

The elimination of "wow" and flutter is as important in this type 
of recording as in any other and is solved in much the same manner by 
the use of rotating mass with suitable mechanical filters and dampers. 

The spooling problem is similar to that in motion pictures with a 
couple of extra heartaches thrown in. The wire must be level- wound 
bobbin fashion, requiring added mechanical devices. An additional 
problem lies in the high speed forward-winding or rewinding of the re- 
cording medium. For certain practical reasons this must be accom- 
plished on the same machine. 

Jan. 1947 



In professional use, where the reproduction must be repeatable 
within very narrow time limits, or where the record is to be used in 
synchronization with other equipment, some sort of synchronous 
drive is a necessity in addition, of course, to driving the wire with a 
nonslipping capstan. Where timing is important only with respect to 
total length of recording, as in the broadcasting industry, a synchro- 
nous motor, driven from a stable power supply, is sufficient. Where the 
device must be locked in synchronization with parallel acting devices, 
such as film cameras, projectors, or other recorder-reproducers an 
interlock type of motor is applicable. 

FIG. 1. Front view of Magnicorder Type SD-1. 

Most of the above-mentioned mechanical features are incorporated 
in the design of the Magnecorder, Type SD-1. The jam-type capstan 
is machined to close tolerance after mounting it on the flywheel shaft. 
This shaft runs in sleeve bearings and is driven through suitable speed 
reducers by a synchronous motor. A timer calibrated in minutes and 
seconds is provided. This could also be calibrated in feet, if desired. 
Appropriate reversible spooling and level-winding mechanisms are 
driven from the capstan shaft. The wire has a slip in the capstan of 
less than one part in 5000 which corresponds to about one second in 

32 R. J. TlNKHAM AND J. S. BOYERS Vol 48, No. 1 

one hour and 23 min of recording. At the wire speed of 4 ft per sec, 
used in this machine, that is the same as saying about a mile of 
wire must pass through the machine before there is a total slippage of 
one foot. 

The unit is furnished in a cabinet (Fig. 1), or it may be mounted in a 
standard 19-in. rack. Console mounting is also available. Remote 
starting, stopping, recording, and playback may be incorporated if 

To damp out flutter caused by the spooling system, the wire passes 
through an antiflutter set of spring loaded pulleys before entering the 
open type combination erase -record head. Following the recording 
head the wire passes over the playback head, then around the capstan, 
over an idler, the level-wind arm, and onto the take-up spool. The 
electrical apparatus is so arranged, that the pickup head may be used 
for either playback or monitoring purposes simultaneously with the 
recording operation. There is a delay of a fraction of a second be- 
tween the recording and playback, caused by the distance between 
the two heads. 

It is often desirable to hasten on to a later portion of the record, or 
to rewind the record rapidly. A mechanical control knob with suit- 
able electrical and mechanical interlocks, shifts gears to drive the wire 
in either direction at a speed ratio of 4 : 1 . Rewind to playing speed 
ratios as high as 30:1 have been used on auxiliary spooling units. 
However, it is not feasible to include such apparatus in the present 
Model SD-1 Magnecorder where accurate wire measuring control is 

Operation of the unit is simple. The wire follows a well-defined 
path and is easily threaded up. Separate switches are provided for 
both the motor and amplifier power. To start the recording operation 
it is necessary only to push a red push-button switch which links up 
the proper electrical circuits to turn on the high-frequency erase and 
bias oscillator. The recording process may be stopped by either push- 
ing the playback button or changing the direction or speed of the wire. 
Electrical interlocks mentioned previously provide this feature. 

A "Volume Unit" meter is included to indicate the correct record- 
ing level. Separate gain controls are provided for the separate re- 
cording and playback (or monitor) channels. These controls utilize 
the bridge T configuration and are of the step-by-step type. 

The magnetic recordings made by Poulsen utilized a recording 
system which might be called the direct current method. In this 


system the recording medium was premagnetized to place it on a 
linear portion of the B-H curve and the magnetization of the record 
was then changed in accordance with the recorded signal. This sys- 
tem suffered from inherent difficulties in signal-to-noise ratio and dis- 

The magnetic recordings of today are generally made using a 
supersonic bias to provide the linear characteristic necessary for a 
large signal-noise ratio with low distortion. 1 Several types of wire 
have been developed but one of the most satisfactory evolved to date 
is composed of solid stainless steel and is 0.004 in. in diameter. This 
wire is manufactured with close tolerances as to both mechanical and 
magnetic characteristics and is available in quantity. Using this 
medium, and with proper selection of the wire speed, machines have 
been made which reproduce from less than 10 cps to over 30,000 cps. 
Signal-to-noise ratios of better than 40 db are regularly achieved in 
production with low distortion in the recorded signal. Signal-to-noise 
ratios in excess of 55 db have been produced under laboratory condi- 

The Magnecorder Model SD-1 requires an input signal of approxi- 
mately zero VU level. The signal is fed through a recording amplifier 
utilizing a single stage of amplification. The output of this amplifier 
is fed through a transformer to the high-frequency pre-equalizer. 
This equalizer introduces a high-frequency boost to compensate for the 
reduced response of the recording heads in the upper portion of the 
frequency range. The recording head has two coils, one for the signal 
frequency and the other for the high-frequency bias current. The in- 
ductance of the signal frequency coil is approximately 2 millihenries 
while the inductance of the bias coil is only a few microhenries. 

The supersonic oscillator utilizes a conventional Hartley circuit and 
supplies power for both bias purposes and erasing the wire. It is quite 
important that the erase field be powerful enough to eradicate com- 
pletely the strongest signal which may be recorded on wires having 
high coercivity. 

The playback head is similar to the recording head but lacks the 
bias coil. The output from this head is approximately 80 db below a 
zero VU level. Its frequency response rises approximately 6 db per 
octave from a low frequency to approximately 1000 cycles. The high 
end of the frequency response begins to fall off at approximately 5000 
cycles, and at 12,000 cycles it is about 15 db down. 

The reproduce amplifier has incorporated within it a low-frequency 

34 R. J. TlNKHAM AND J. S. B OVERS Vol 48, No. 1 

equalizer which boosts 50 cycles approximately 22 db with respect to 
1000 cycles. This compensates for the output of the reproduce head 
and in combination with the pre-equalizer mentioned above results in 
a frequency response which is flat within 2 db from 50 to 12,000 
cycles, and is down 6 db at 15,000. 

The output signal coming from the reproduce amplifier is approxi- 
mately zero VU in level across a 600-ohm load. Distortion in the re- 
produced signal is kept at a low point by careful factory adjustment of 
the operating conditions. The total rms distortion is less than 1.5 
per cent at 1000 cycles. This distortion is not seriously different 
throughout the audio range. 

Numerous applications of wire recorders to the motion picture in- 
dustry have been suggested. The inherent factors of low cost of the 
recording medium, ease of operation, portability, and ruggedness lend 
this system to many operations where other methods have serious 

It has been suggested that a wire recorder might be used to record 
the original sound while making the picture. The wire could be edited 
in much the same manner as the movie film is edited and finally in- 
corporated with other wires to form the final wire. The sound could 
then be dubbed to the final negative used to print the release. Sav- 
ings in film through the use of this system for intermediate recording 
would be tremendous without any sacrifice of sound quality. 

Editing is done merely by snipping the wire with scissors, splicing it 
with square knots, and then trimming off the ends. The knots ride 
over the reproducing heads with no perceptible interference during 
modulated passages. 

If mistakes are made in the recording of either music or dialogue 
it is not necessary to discard the entire take. The recording may be 
reproduced to the performer, and, at the appropriate time, the re- 
cording button may be pushed, whereupon the performer repeats 
that passage which was previously in error. The recorder performs 
the operations both of erasing the previously recorded incorrect 
signal and dubbing in the correct program in its proper sequence. 
This has been demonstrated many times in both dialogue and music. 

The recording of incidental sounds and sound effects may be made 
advantageously on wire. Here the fact that the wire does not de- 
teriorate with repeated playings is a valuable feature. Recordings 
have been reproduced for several thousands of times with no appre- 
ciable impairment of the signal. 


With suitable mechanical means it would be possible for the ama- 
teur to make his own sound recordings and reproduce them in syn- 
chronism with the picture. This system might also be utilized for 
providing sound with rushes which are normally silent. This record- 
ing system is ideally suited to dialogue rehearsals. In these applica- 
tions the immediate playback feature of the wire and its low cost are 
obvious advantages. 

Industrial films, where the cost must be kept as low as possible, can 
use wire recorders to great advantage in view of the small cost as 
compared with film recording methods. 

Location recording is more enjoyable with less bulky equipment. 

In conclusion, the authors do not mean to suggest that magnetic 
recording offers the industry a cure-all for recorded sound. There re- 
main problems to be worked out in its specific application to the mo- 
tion picture art. However, it does offer certain advantages not found 
in other systems of recording. 


1 CAMRAS, M. : "A New Magnetic Wire Recorder," Radio News, 30 (Radionics 
Section 1, Nov. 1943), p. 3. 



Summary. The object of this paper is to discuss the application of coated paper 
tape as a magnetic sound recording medium. The special features of this interesting 
new development which may render it desirable for many commercial uses are pointed 
out. Current trends in recorder design are discussed. A brief summary of tape 
recorder performance is given, including dynamic range, frequency response, and 
distortion characteristics. Some special features of the new recording medium rela- 
tive to its possible use in the motion picture industry are pointed out. 

In order to portray the present status of magnetic recording on 
coated media, it is necessary to mention briefly its history. The art 
is not new, but the techniques and equipment have progressed far 
beyond those of Poulsen, who devised the first magnetic sound re- 
corder 50 years ago. Through the intervening years, many investi- 
gators have tried to achieve acceptable fidelity and length of recording 
time, but it was not until the advent of the Camras 1 wire recorder 
that this goal was reached. During World War II, the wire recorder 
served well in our armed forces and was used extensively throughout 
the world. 

It was recognized many years ago that certain fundamental ad- 
vantages could be gained by the use of a flat ribbon or tape for the 
recording medium, but these were overbalanced by the high speed at 
which it was necessary to operate the tape and the cumbersome reels 
which were required to maintain a satisfactory playing time. Some 
of the first powder tapes were coated with finely ground iron pow- 
ders having relatively poor permanent magnet properties. 

For several years before the war, and until it ended, the Germans 2 
had achieved a large measure of perfection in equipment using mag- 
netic powder coated media instead of wire. This was accomplished in 
spite of the relatively poor permanent magnetic properties of the iron 
oxide powders (gamma phase Fe^Oz) employed as a coating material 
for these tapes. 

* Presented Oct. 24, 1946, at the SMPE Convention in Hollywood. 
* * Indiana Steel Products Company, Chicago, 111. 




Magnetics of Magnetic Sound Recording Media. The per- 
formance of any magnetic sound recording medium depends greatly 
upon its magnetic properties. Since reference must frequently be 
made to the properties of permanent magnet materials in order to 
deal properly with the present subject, a brief review of these prop- 
erties is in order for the benefit of those who may not be familiar 
with the terminology. The two most important properties of a perma- 
nent magnet as applied to magnetic sound recording are remanent 
magnetism and coercive force. Simply stated, remanence is the mag- 
netic induction remaining in a magnet after an applied magnetizing 
force is removed. The applied magnetizing force may be produced 
either by a coil of wire carrying an electric current or by another 
permanent magnet held in close proximity. Coercive force can be 
broadly defined as its resistance to demagnetization. More spe- 


1. Normal magnetization curve 
hysteresis loop. 


cifically, the coercive force in oersteds is the value of the applied de- 
magnetizing field in a closed magnetic circuit required to reduce the 
magnetic induction to zero. 

Fig. 1 is a hysteresis loop typical of a material having permanent 
magnet properties. Holmes and Clark, 3 and more recently Camras, 4 
have discussed the relationship of the sound recording performance of 
wire and its magnetic properties. A magnetic record of sound along a 
wire or tape may be described simply as a variation in the intensity of 
magnetization produced by the magnetism from the recording head. 
Therefore, it can be seen by inspection of Fig. 2 that the external 
magnetic field extending from the surface of the tape coating will 
determine the energy that is usable in reproducing a sound record. 
In any case this external magnetic field is dependent upon the mag- 



Vol 48, No. 1 

nitude of the internal magnetic induction in the tape and the mag- 
netizing force. Special techniques in the use of supersonic magnetiz- 
ing fields in connection with the audio frequency magnetizing field as- 
sures a linear and distortion-free magnetic sound record. 

The density of the usable external field in a magnetic record of 
sound over a wide range of frequencies is rather complex in that, at 
the lower audio frequencies, it is most influenced by the magnetic 
remanence of the magnetic material and at the higher audio fre- 
quencies it is most influenced by its resistance to demagnetization. 
The large self -demagnetization factor of short magnets is very im- 
portant since it influences the required inherent coercive force of the 





FiG. 2. Sinusoidal flux configuration on a 
magnetic sound record. 

magnetic material. For this reason, the physical dimensions of the 
recording medium, whether it be a wire, or a thin coating of magnetic 
powders, must be taken into consideration in any appraisal of per- 
formance at the higher audio frequencies. 

Magnetic Materials for Powder Coatings. Progress in the de- 
velopment of coated magnetic tapes in this country during and 
since the war has resulted from several independently conducted 
research programs and has been responsible for the development of 
both metallic and oxide powders having permanent magnet proper- 
ties superior to the German product. One such program initiated 
by the author has resulted in the development of a metallic coating 


having permanent magnet properties approaching those of some of 
the well-known Alnico alloys, yet bearing no metallurgical resemblance 
to them. This material produced in the finely divided state has been 
applied to paper tape and is known as Hyflux. 

The oxide materials which have been and are still being investi- 
gated fall into two general composition types. The magnetic ferric 
oxide (gamma phase FezOz) seems to have been used exclusively by 
the Germans. Investigators in this country, so far, seem to prefer 
magnetite and special variations of ferrous and ferroso-ferric oxides 
of the type (Fe^O^) produced by special methods and thermal treat- 
ment. While coercive forces of as high as 350 oersteds have been 
reported for specially processed ferrous oxide, most of the available 
experimental oxide tapes have coercive forces of less than 200 oersteds. 

The recently announced metallic coated tape, Hyflux, has been 
produced with a coercive force of from 350 to 550. Hyflux powder, 
when compacted to form solid bar magnets, compares in general mag- 
netic properties with other solid permanent magnet materials as 
follows : 


Density Residual Coercive Product 

Grams Induction B r Force He Bd Hd 

per cc Gauss Oersteds max X 10 6 

Hyflux 2.81 2255 550 0.35 

Hyflux 4.9 6610 390 0.97 

Hyflux 4.96 7460 395 1.14 

Magnetite 2.62 1600 190 0.09 

Alnico III 6.9 6900 475 1.35 

Any of the above materials, when finely ground to have particle 
sizes of one micron or less, would exhibit values of residual induction 
much lower than indicated for the solid state. The values for coercive 
force usually increase with decrease in density. This is particularly 
noticeable in the case of Hyflux. 

Hyflux is produced by a unique process resulting in a very unusual 
physical structure, which may be a fundamental factor in the attain- 
ment of its surprising permanent magnet properties. An extensive 
investigation is being continued to establish a more complete under- 
standing of this condition. 

Sound Recorder Performance. It should be understood that any 
presentation of data on the performance of magnetic sound recording 
media is limited by the conditions under which testing procedures 
have been conducted. Much of the performance data presented in 



Vol 48, No. 1 

current literature is subject to various interpretations, depending on 
the equipment and the components used and the choice of parameters. 
Until such time as standardization factors can be established, it will 
be necessary to accept the data presented here as comparative values 
obtained under certain specific conditions. 

Constant current response curves have been found to be greatly 
dependent on recording head design and materials. Theoretical re- 
sponse based on tape speed, gap length, etc., is often masked by the 
more practical factors of core loss, permeability, and saturation char- 
acteristics of the head. A head with a low copper-to-iron ratio will 


ttrfLl/X TAPE 
H.F.BIAS 1 10 MA. tOKC 




FIG. 3. 

be more efficient at the lower frequencies than at the upper end of the 
audio range at low tape speeds. This may be more desirable than 
high-frequency efficiency at the expense of the low, because most of 
the background noise has been found to be in the lower frequency 

The constant current response curve in Fig. 3 was made with a 
laminated head of low copper-to-iron ratio under the conditions 
indicated. Under the same conditions of tape speed, gap length, etc., 
but with a different head, the peak may be moved forward by more 
than a thousand cycles at the expense of the lower frequency output 
as shown in the dotted line curve. The response of the head used in 

Jan. 1947 



making the second curve was substantially flat from 50 to 10,000 cps. 

During the past two years, several sound recorders have been built 
to use Hyflux tape. Fig. 4 shows the over-all response of one of these 
machines. While the useful response is limited to within a 6000 cycle 
range because of the slow tape speed (8 in. per sec) recent research 
indicates that even at this slow speed the useful range might be in- 
creased to above 7000 cps through improved head design. The dy- 
namic range is in the neighborhood of 40 db with less than 5 per cent 

Fig. 5 shows input-output curves on Hyflux tape at three frequen- 
cies: 100, 1000, and 3000 cps. The point at which the curves begin 


FIG. 4. Over-all recorder response Hyflux tape at 8 in. per sec. 

to deviate from a 45-deg line by one decibel was taken as the point at 
which maximum undistorted output occurred. Since these points 
do not occur at the same input levels at the three different frequen- 
cies, it is evident that a rising characteristic is necessary for recording 
in order to prevent distortion at the lower frequencies. For example, 
a characteristic rising 3 db per octave from 100 to 1000 cps and 6 
db per octave from 1000 to 3000 cps would be very nearly ideal for 
this system. 

Hyflux tape requires a much higher supersonic biasing field than 
any of the oxide tapes. The required bias current under a given set of 
test conditions appears to be a function of the coercive force of the 


H. A. Ho WELL 

Vol 48, No. 1 

recording medium. Fig. 6 shows noise and output versus bias char- 
acteristics of Hyflux tape. After roughly determining the proper 
audio input levels for each frequency, the three curves shown for 
1000, 3000, and 4000 cps were run. Then with no audio input, the 
noise level was checked as a function of bias current. The optimum 
bias current was then selected by noting the point at which the maxi- 
mum signal-to-noise ratio occurred. 

It is significant that in all of the foregoing results constant field 
saturation was employed in erasing. This was accomplished by means 
of a small permanent magnet which subjected the tape to a longi- 
tudinal field of about 2000 oersteds. There is evidence indicating that 




INPUT OS (^ fOC 08= 001 *UP} 

FIG. 5. 

a significant improvement in signal-to-noise ratio might result if high- 
frequency erasing were used. The high coercive force of Hyflux intro- 
duces some difficulty in high-frequency erase head design, although it 
has been reported that such heads have been made to function satis- 

Choice of Paper As a Backing Material. The question may arise 
as to why paper was chosen as a base for Hyflux magnetic coating. 
During the early stages of the development it was necessary to de- 
vote considerable time on experimental tape pulling mechanisms. 
It soon became apparent that, in order to eliminate wow and flutter, 
a very rugged, positive grip, driving capstan was necessary. Such a 

Jan. 1947 



mechanism, if effective, is not inherently gentle on such fragile mate- 
rials as plastic ribbons and the weaker grades of paper. Therefore, 
a special paper was chosen because of its superior dimensional sta- 
bility and physical strength. Experience has shown that any mate- 
rial that stretches, tears easily, or becomes distorted under stress 
will be seriously impaired in its performance or fail completely. This 
is particularly important when the backing medium is 0.002 in. or 
less in thickness. On the other hand, coated cellulose acetate or 
other plastic backing results in somewhat less surface noise by virtue 
of its smoother finish. The use of a composite paper-plastic ribbon 



Noise level and output versus bias current for Hyflux tape. 

has been suggested in order to take advantage of both the excellent 
dimensional stability of paper and the more uniform surface finish 
of plastic ribbons. 

In addition to its superior dimensional stability, paper has the 
advantage of being easier to handle, edit, and repair. The uncoated 
side can be utilized for markings, such as time, footage, synchroniza- 
tion, indexing, etc. From the manufacturing standpoint, its good 
handling properties and cheapness are important factors. 

At the present time, most coated magnetic tapes have been pro- 
duced in Y4-in. widths, although there has been no move to standard- 
ize this dimension. As a matter of fact, coated magnetic recording 

44 H. A. HOWELL Vol 48, No. 1 

media can be produced to meet almost any specification in sheets, 
disks, ribbons, or bands. Techniques for production are being estab- 
lished and uniformity of output will be assured through the thousands 
of feet being produced for developmental purposes. 

Trends in Recorder Design. Few recorders designed to use 
coated tapes have been built in this country. Most of these have 
been engineered to meet the requirements of the home recording 
enthusiast, and none, so far as the writer knows, has reached the 

One model now being planned will have a frequency range of from 
50 to 9000 cps, and will be suitable for commercial recording. During 

FIG. 7. Simplified magnetic tape recorder mechanism. 

the coming year, there will no doubt be a number of commercial 
high-fidelity tape recorders produced. Most of present day experi- 
mental tape recorders use 8-mm film reels with the 1 /4-in. coated rib- 

Fig. 7 is a simplified version of a mechanism suitable for use in 
coated tape sound recorders. The tape runs from supply reel A over 
the erase head B which is energized only when recording; then over 
the combination recording and reproducing head C to the driving 
capstan D and to the take-up reel E which is driven by a suitable 
take-up mechanism. Most of the present experimental recorders 
have been constructed with a fast rewind feature. The relatively 


slow speed required for any frequency response requirement, coupled 
with the absence of the troublesome level wind mechanism necessary 
on wire recorders, greatly simplifies the mechanical design of coated 
tape sound recorders. The greater sound energy level on the tape 
itself so simplifies the electronic design that a high gain amplifier is 
unnecessary. For example, one model designed for use with Hyflux 
tape utilizes an amplifier having an over-all gain of only 30 db and 
delivers 10 w. 

Application in the Motion Picture Industry. The author does 
not feel qualified to specify where coated tape magnetic recorders 
might fit in the motion picture field. However, some features which 
may be attractive will be pointed out. 

Coated tape or ribbons of paper can be perforated the same as 35- 
mm film. The tough grades of paper now available should withstand 
sufficient use in sound track work. The recording can be monitored 
directly from the magnetic record while being made, so that the sound 
for retakes can be made immediately. Magnetic powder coatings 
can be applied directly to 16-mm film, thus making possible a ready- 
to-use sound track during exposure in the camera. Such coatings can 
be made to withstand any of the reversal and processing operations. 
Duplicates of a 35-mm master with magnetic sound might be pro- 
duced in the usual manner with a photo sound track. Magnetic 
sound recorders are insensitive to the motion of vehicles or other 
similar conditions. Multitrack sound effect records could be ar- 
ranged so that any one of several could be made available at the touch 
of a button. 

Acknowledgments. Grateful acknowledgement is made to 
Harold L. Stout, of Midwest Research Institute, Kansas City, 
Missouri, for part of the response data; Dr. Robert C. McMaster, 
Battelle Memorial Institute, Columbus, Ohio, for some of the mag- 
netic test data; and to Marvin Camras, Armour Research Founda- 
tion, Chicago, Illinois, for help in establishing the testing methods. 


1 CAMRAS, MARVIN: "A New Magnetic Wire Recorder," Radio News (Nov. 
1943), p. 3. 

2 Report C-59, "The Magnetophone," U. S. Army Intelligence Report on 
Captured Enemy Equipment Lib., U. S. Department of Agriculture, Washing- 
ton, D. C. 

3 HOLMES, L. C., AND CLARK, D. L.: "Supersonic Bias for Magnetic Record- 
ing," Electronics (July 1945). 

46 H. A. Ho WELL Vol 48, No. 1 

4 CAMRAS, MARVIN: "Theoretical Response from a Magnetic Wire Record," 
Proc. I.R.E. and Waves and Elecrons, 34, 8(Aug. 1946), p. 597. 


BEGUN, S. J.: "Magnetic Recording and Some of its Applications in the 
Broadcast Field," Proc. I.R.E. (Aug. 1941), p. 423. 

TOOMIN, H., AND WILDFEUER, D. : "The Mechanism of Supersonic Fre- 
quencies as Applied to Magnetic Recording," Proc. I.R.E. (Nov. 1944), p. 664. 

HICKMAN, C. N. : "Sound Recording on Magnetic Tape," Bell Sys. Tech. 
Jour. (June 1937), p. 165. 


MR. GEORGE TALLIAN: I would like to know if this process is applied to an 
existing film for instance, a 16-mm film which is already processed and already 
bears a picture will it in any way detract from the picture? Do you have to 
put it through any kind of a chemical bath, or in any way spoil the quality of the 
image that is already on the film? 

MR. HOWELL: No, I do not think so. This is a coating that can be placed in 
any convenient location on the film, on either 16- or 35-mm, as Mr. Camras has 
demonstrated. 1 Usually it is put on the outside in the very small area away from 
the sprocket holes, and there is no processing required. It can be monitored 
at the same time you are making the recording, for that matter, and has no 
effect whatsoever on the picture. 

MR. TALLIAN: I noticed that the samples Mr. Camras 1 demonstrated were 
badly warped. Now, for instance, in a 16-mm film we will have trouble focusing 
it in a projector if we have a coating which makes the film warped. 

MR. HOWELL: I agree there is somewhat of a problem, but we shall be able to 
overcome that. Naturally, if you get one side thicker than the other, it is going 
to cause trouble. 

MR. J. I. CRABTREE: What is the resistivity of the coating on the paper to 
wear? What is its propensity to becoming scratched and therefore giving you 
ground noise? 

MR. HOWELL: Scratches on a magnetic coating ordinarily do not affect its 
performance unless it is excessive. Ordinary scratches such as that experienced 
in film running through a machine, I doubt very much if it would ever cause any 
trouble. However, we do have the problem of adherence. Of course, that is 
purely a problem of organic chemistry and plastics, and we have seen some coat- 
ings that are very good. 

MR. CRABTREE: I thought this was paper, not film. 

MR. HOWELL: This machine uses paper 0.002 in. thick, including the coating, 
but the magnetic material itself can be put on any type of backing medium like 
film, thread, or paper ribbon. 

1 CAMRAS, M.: "Magnetic Sound for Motion Pictures," /. Soc, Mot, Pict, 
, t 48, 1 (Jan, 1947), p, 14. 


MR. E. W. KELLOGG: How well does the surface stand repeated running? 
Does it tend to roughen, or does it polish down? You gave a figure for coercive 
force. Was that for the material as powder, or was that the powder applied in 
the form of tape coating? 

MR. HOWELL: The material is produced in a finely divided form. The in- 
dividual particles are in the range of two-tenths to one micron. This is the in- 
herent physical properties owing to the process used in production. Its coercive 
force and other magnetic properties are there from the very beginning. The 
processing operation of dispersing it and producing it in paint form that can be 
applied to a paper or ribbon should not have any effect on its magnetic proper- 
ties. The coercive force is just inherent with the material and the process used 
in producing it. 

MR. SETHMIRE: Do you have any figures on the uniformity of the coating? 
That is to say, do you record a constant tone on it? How uniform does it play 

MR. HOWELL: I have no scientific data on that. However, I have observed 
tones being played back to show a variation in some cases; but I attributed 
that more to poor resolution between the head and the tape. You see, paper is 
inherently a rough material. With a very smooth backing medium and using 
good techniques in coating, I should say that you should not have any appre- 
ciable variation in output. 

MR. GEORGE LEWIN : Do you have any figures on how this material stands up 
over a long period of time under various atmospheric conditions? Does it oxi- 

MR. HOWELL: We have very little data outside of those which we have ob- 
served during the past three years, experimenting. We have tapes made three 
years ago on which there is no apparent decomposition. Hyflux is of such material 
that if it is subjected to long periods in moist salt air, it would no doubt suffer a 
certain amount of deterioration. However, the material, even though it does 
become completely oxidized, will still reproduce and can be used for recording. 
Under the very worst conditions, the drop should not exceed 6 db. 

MR. LEWIN : You mean, all it does is give you a lower level? 

MR. HOWELL: Exactly. 

MR. J. F. CLARK: What data do you have on the signal-to-noise ratio over the 
entire frequency range under optimum bias conditions? 

MR. HOWELL: It is a little hard to explain that because we have been using 
permanent magnet erasing for convenience, and because of laziness, we have 
not taken the time to design a high-frequency erase device. I would say that the 
signal-to-noise ratio at 1000 cycles is better than 40 db, and would probably im- 
prove if high-frequency erasing were used. There seems to be very little noise 
if the tape is properly erased. It is my guess that the slow tape speed contributes 
to freedom from noise. 

DR. J. G. FRAYNE : In making any value for signal-to-noise, I think it would be 
of interest to know what the width of the sound track is. 

MR. HOWELL: We have used sound tracks on the entire width of V4-in. ribbon. 
However, we have made experiments on sound tracks as small as Vs2 in. It seems 
that the wider the track the less noise you will have. I do not feel qualified to 

48 H. A. Ho WELL Vol 48, No. 1 

describe that relationship, but it is something like 3 db better if you have a track 
width doubled. Is that right? 

DR. FRAYNE: That is right. 

MR. HOWELL: But I have heard some pretty good recording on tracks of 
around Vie in. wide. 

MR. CLARK: Are there any low-frequency variations in the tape response 
such as occur on some of those slides? 

MR. HOWELL: We did not use a French curve. We can plot the curve only 
a few cycles apart and find no bumps anywhere from 25 to 400 cycles. 

MR. LEWIN: Do you have any data on splicing, and so forth, the ease or the 
difficulty with which you can make splices? 

MR. HOWELL: With a little practice one can make a splice in about 5 or 10 
sec that is impossible to notice in going over the recording head. Someone 
asked a while ago about the repeated use; what effect it had on the coating. 
So far, we have found that up to a certain extent repeated use improves the me- 
dium by smoothing off some of the irregularities that might exist there after 
processing the tape. As to the number of playbacks, I am not prepared to give 
you an idea, exactly; but I have run loops as much as 4000 or 5000 times with 
no appreciable drop in output. I have never measured the drop. It would 
stand to reason, with a coercive force of 500, that very little drop would occur 
owing to magnetic depreciation. 

MR. R. C. HOLSLAG : What is the speed of the tape in this machine? 

MR. HOWELL: The last time I clocked it, it was 8.4 in. per sec, in contrast to the 
7 J /2 in. per sec used by Dr. Begun. 2 

DR. FRAYNE : As a metallurgist, can you advise us as to the relative merits from 
a performance standpoint of this magnetic coated tape and a solid metallic 

MR. HOWELL: I have never been connected with the manufacture of steel 
tape. I have never had any experience in processing it. But so far, we believe 
that this material can be processed in very large quantities from a large batch 
that has been homogenized, and that we can predict very uniform results with 
enlarged volume production. 

MR. ALLEN JACOBS : If you doubled the speed of the tape, how good would it be? 

MR. HOWELL: That is something I believe Mr. Camras or Mr. Holmes could 
answer better than I. Ordinarily, the faster you run the medium, the better 
your high-frequency response will be. I would say it almost doubles the range. 
Anyway, there is considerable increase in high-frequency response as you increase 
the speed of the recording medium. 

MR. JACOBS: What is the fastest you have ever used it? 

MR. HOWELL: I have never had any tests made in the laboratory over 18 in. 
per sec. However, we have constant current response data from people who have 
run it up to 4 ft. per sec. 

MR. JACOBS: How good does it get at 18 in.? 

MR. HOWELL : At 4 ft I believe it shows the peaks at around 6000 or 7000 cycles. 

2 BEGUN, S. J.: "Recent Developments in the Field of Magnetic Recording," 
/. Soc. Mot. Pict., 48, 1 (Jan. 1947), p. 1. 


MR. KELLOGG: Can you give us an idea of what percentage, either by weight 
or as metal, and how much plastic it contains after it is dried out? 

MR. HOWELL: The material is metallic in nature and naturally the mag- 
netic density in the coating will depend on how much of the metal you use. 
You necessarily have to use a certain amount of bonding material to keep it to- 
gether and make it adhere to the paper not more than 10 per cent, ordinarily, if 
you use a properly chosen material. 

MR. KELLOGG: Is that by volume or weight? 

MR. HOWELL: By volume. 


Summary. The following notes on discussions held at two meetings of the 
Research Council Basic Sound Committee concern the use of magnetic recording in 
motion picture studios. These meetings were held for a general discussion between 
the designers and manufacturers of magnetic recording and reproducing equipment 
and studio sound personnel for two reasons: (1) to allow the manufacturer to have an 
idea of the possible uses of their equipment and to obtain very general specifications 
on equipment to fulfill these uses, and (2) to allow studio personnel to obtain an idea 
of the present and possible future capabilities of magnetic systems. 

It should be realized that definite conclusions have not yet been reached and the 
recommendations contained herein are very tentative. 

The Research Council Basic Sound Committee has set up a Subcommittee on 
Magnetic Recording. This subcommittee is available to answer questions concerning 
studio practices and recording and reproducing equipment and will co-operate actively 
with those interested in the design, development, and manufacture of magnetic record- 
ing and reproducing equipment. Inquiries to this subcommittee may be addressed 
to the Research Council, 1217 Taft Building, Hollywood 28, Calif. 

Meeting of Oct. 24, 1946. A meeting of the Basic Sound 
Committee of the Research Council was held on Thursday, Oct. 24, 
1946, at 4:30 P.M., in the Registration Room of the Hollywood 
Roosevelt Hotel. L. L. Ryder, Chairman, opened the meeting by 
explaining that the purpose was to have a general discussion between 
the designers and manufacturers of magnetic recorders and studio 
sound personnel interested in possible uses in recording studios. 
This procedure allows the manufacturer to have an idea of the 
possible uses of their equipment and to obtain very general specifica- 
tions. Also, it allows the studio people to obtain an idea of the 
present and possible future capabilities of the magnetic recording 

The question was asked, "Are the manufacturers interested in 
developing a magnetic recorder for synchronized operation?" The 
resulting comments follow: 

(1) The Indiana Steel Company believes that some types of 

* Research Council, Academy of Motion Picture Arts and Sciences, Holly- 
wood, Calif. ; dated Jan. 9, 1947. 


paper or cellulose acetate could be adapted to a magnetic material 
coating. Either would make synchronized operation possible. 

(2) The Magnecord Company now has magnetic wire which at 
present is "non-sync." However, the company is interested in 
"sync" operation and believes that it may be possible to sync wire 
recordings automatically. 

(3) The Armour Research Foundation is not a manufacturing 
company, but concerns itself primarily with fundamental research 
and development. This company's representative offered to dis- 
seminate to Armour's licensees the information obtained at this 
meeting. If these licensees are interested, (and it is believed they 
are), the Foundation will investigate the problem. 

(4) The Brush Development Company is interested in both 
phases; that is, sync and non-sync. The company is now using 
both the wire and the tape. 

Suggestions on possible studio uses of magnetic recorders listed 
below were made, and incorporated into this material are the results 
of subsequent discussions on the quality necessary for each applica- 
tion. The quality requirements are broken down into three classifi- 
cations : 

Quality A. Quality at least as good as present original motion picture re- 
cordings. This quality is necessary in any recording subsequently rerecorded 
and used as part of the release or any recording which is used as a playback check 
of original material. 

Quality B. Quality between Quality A and the commercial quality now 
available for amateur and home- type recorders. This type record is used as a 
guide or tool in the making of pictures but not in the release. 

Quality C. Quality C is the commercial quality now available for amateur 
and home use. 

Sync or 

Items Quality Non-Sync 

1. Original recordings, both dialogue and 

music A Sync 

2. Playbacks 

(a) Check of original material A Sync 
(6) For directorial purposes, such as 

rehearsals, etc. B Sync 

3. Location sound effects A Non-sync 

4. Talent tests A Sync 

5. Prescoring 

(a) For release A Sync 

(6) Temporary rerecordings B Sync 



Vol 48, No. 1 


6. Creating reverberation 

7. Signal delay mechanism for noise re- 


8. Cue tracks 

9. Dialogue rehearsals such as dialect 

10. Audience reaction 

11. Presetting dials for rerecording 

12. Timing of special effects 




Sync or 



B Non-sync 

C Sync 

A, B, or C, 


on amount Sync 

of control Sync 

provided by 

the device 

Dr. Begun stated that before the magnetic recorder manufacturers 
could proceed with the development of equipment suitable for studio 
use, it would first be necessary to know quality requirements of the 
studios. Do the studios want a recorder superior in quality to that 
of present film recorders, or one that is equivalent? 

In reply to this question, the following studio requirements were 
given (in addition to those which have been incorporated into the 
list of suggested uses) : 

(1) Release Sound Track. At the moment, at least, there has been 
no consideration given to the magnetic recording medium for release 

(2) Production Recording. For production recording of dialogue 
and music, a quality comparable to present film recording quality 
would be necessary. 

(3) Currently, the Following Frequency Ranges Are Used. For 
dialogue, from about 80 cycles to between 7000 and 8000 cycles; 
for music, from about 50 cycles to between 7000 and 8000 cycles. 
This means that the equipment must be of high quality from 50 to 
10,000 cycles. 

(4) Volume Range. With film the range is about 48 db from 
maximum modulation to no signal with noise-reduction applied. 
Through the use of push-pull, reverse bias, pre- and post-equalization, 
etc., it is possible to get a volume range up to 55 db. Through over- 
load, for instance, in sound effects passages, a range of 60 to 65 db 
may be obtained. It should be noted that even this type of overload 
must not destroy the character of the sound. While going into 


overload is not desirable, it indicates a need for a greater volume 
range. Our present effective range in the theater may at times be 
as low as 40 db. 

(5) Speed. The speed should be 90 ft per min for the purposes 
of synchronizing and editing. Any other speed must have a very 
important advantage to be given consideration. 

(6) Distortion. Film distortions are in a range from one to two 
per cent total harmonic distortion between 400 and 1000 cycles. 
This distortion increases with frequency and is in the neighborhood 
of four per cent at 3000 cycles. 

In transmission equipment, the total harmonic distortion is one 
per cent or less through the useful frequency and volume ranges ; in 
theater equipment this total harmonic distortion is two per cent or 
less at full power output. These figures are quoted to show that 
distortions in film recording and film reproducing equipment are 
not in the order of five to eight per cent. 

Although these figures are given in terms of total harmonic dis- 
tortion, the industry uses intermodulation and cross-modulation tests 
for determining distortion. The Council's Basic Sound Committee 
is now correlating this information and expects to have available, in 
the near future, maximum allowable distortion in percentage inter- 
modulation and cross-modulation. 

Although distortion measurements are used to check and maintain 
equipment, listening tests are the final criterion in determining 

(7) Flutter. A magnetic recorder should have a flutter content 
of not more than =*= Yio of one per cent, based on the operation of 
present film recording equipment. 

(8) Slating. The recording medium should be capable of accept- 
ing visual marks for identifying and synchronizing purposes. 

(9) Edge and Code Numbers. Edge numbers, placed on negative 
film by the manufacturer, are visible on raw stock and print through 
onto the print. These numbers are used for identification purposes 
on both picture and sound negative until the picture and sound 
release negatives have been finally assembled. It would be a great 
convenience if the recording medium were capable of accepting such 
numbers for purposes of identification. 

Code numbers are numbers which are added to the separate 
picture and sound work prints for purposes of easy synchronizing 
and identification in the studio. These numbers are in addition 


to negative edge numbers and run consecutively through each reel, 
identifying both the reel and the sequence in the print as assembled. 
Code numbers are used throughout the editorial procedure. Here 
again, it would be of great convenience to be able to code the record- 
ing medium. This could be accomplished if the recording medium 
were capable of taking ink. 

(10) Duplication. For protection, editorial, and other purposes, 
duplication (through rerecording) should be available with no greater 
loss from the original to the duplicate than now obtained in film from 
the negative to the print. 

(11) Durability. The recording medium must be as durable as 
film, from handling, projection, and storage standpoints. Prints are 
projected from 50 to 500 times. 

(12) Perforations. The ability to perforate the recording medium 
for editorial and synchronizing purposes would be advantageous. 
Thirty-five millimeter perforations on a single side of the recording 
medium would probably be satisfactory for studio use.* 

(13) Splicing and Blooping. Quick and accurate splicing would 
be an advantage for editorial purposes and it must be possible to 
"bloop" all splices. 

(14) Shock Resistance. The magnetic recorder must be capable 
of withstanding normal handling in all types of transportation. 
Ordinary shock and vibration during such transportation should not 
affect the operation of the modulator. 

(15) Safety Base. The base carrying the recording medium and 
the recording medium itself should burn at a rate comparable to 
acetate film and not nitrate film. 

(16) Volume Compression and Expansion. Volume compression 
and expansion might be given consideration for future use. 

* Subsequent to the meeting, it was suggested that consideration be given to 
the width of the recording medium from the following three standpoints: 

(1) What width should the recording medium have, considering the necessary 
equipment changeover? Should 35-mm width be given preferred consideration, 
as there would be no difference in the handling procedures? 

(2} Should it be possible to make two magnetic recordings simultaneously 
on the same recorder; one to be used as a negative, the other to be used as a 

(.?) Would it be advantageous to be able to make a photographic image and 
a magnetic image simultaneously on a combination recorder? 


(17) Push-Pull Sound Tracks. Push-pull sound tracks are not 
necessary if satisfactory quality can be obtained without their use. 

It was pointed out to the manufacturers present that it would be 
the responsibility of the manufacturer to indemnify, patentwise, 
the equipment for the studios. 

It was pointed out that in giving consideration to the design of 
magnetic recorders for studio use, it should be realized that while 
important savings can be effected by a reduction in the cost of re- 
cording medium, more important savings can result from equipment 
which saves production time. 

Mr. Ryder explained that the suggestions and statements made 
at the meeting were not intended to direct the manufacturers' efforts 
but rather to familiarize the manufacturers with studio problems. 

Those attending the meeting were: 

L. L. RYDER, Chairman 

Paramount Studio 

S. J. BEGUN Brush Development Company 

P. E. BRIGANDI RKO-Radio Studio 

MARVIN CAMRAS Armour Research Foundation 

J. P. CORCORAN Twentieth Century-Fox Studio 

CHARLES FELSTEAD Universal-International Studio 

BLAIR FOLDS Brush Development Company 

L. T. GOLDSMITH Warner Bros. Studio 

H. A. HOWELL Indiana Steel Products Co. 

W. F. KELLEY Mgr., Research Council 

H. A. LEEDY Armour Research Foundation 

W. E. McKiBBON Indiana Steel Products Co. 

J. W. McNAiR American Standards Association 

BOYCE NEMEC Engr. Secy., Society of Motion Picture Engineers 

W. V. STANCIL Consulting Engineer 

J. A. STRANSKY Republic Studio 

R. J. TINKHAM Magnecord, Inc. 

Meeting of Nov. 20, 1946. The second meeting of the Re- 
search Council Basic Sound Committee to discuss magnetic recording 
was held on Wednesday, Nov. 20, 1946, at 12:30 P.M., in Hollywood, 
Calif. At this meeting the notes of the committee's meeting of 
October 24 were reviewed and again discussed. The committee 
was still in agreement with the comments and statements included 
in the information distributed on Oct. 24, 1946. It was decided : 

(a) That the recording time should be at least 11 min of con- 
tinuous recording, 


(b) That the rewind time should be less than the recording time 
and it would be very desirable to have a rewind time of one minute, 

(c) That it would be very desirable to have an operating time such 
that the recording medium has acquired constant speed ready for 
recording in three seconds from the time the recording motors are 

(d) That the width of the recording medium should be one of the 
following: 35-mm, l^/Vmm, 16-mm, or 8-mm. 

It was also decided that a subcommittee will be appointed by the 
Basic Sound Committee, which will closely follow the progress in 
the development of magnetic recording, will co-operate with those 
interested in the development and manufacture of magnetic recording 
and reproducing equipment, and will be available to answer questions 
concerning studio practices and studio recording equipment. Any 
inquiries to this committee should be addressed to the office of the 
Research Council to the attention of the Subcommittee on Magnetic 

The meeting was attended by the following: 

L. L. RYDER, Chairman 

Paramount Studio 

P. E. BRIGANDI RKO-Radio Studio 
G. A. BURNS Metro-Goldwyn-Mayer Studio 

L. I. CAREY Universal-International Studio 

W. F. KELLEY Mgr., Research Council 

J. P. LIVADARY Columbia Studio 
W. C. MILLER Metro-Goldwyn-Mayer Studio 

W. A. MUELLER Warner Bros. Studio 
' ELMER RAGUSE Hal Roach Studio 
J. A. STRANSKY Republic Studio 
F. R. WILSON Samuel Goldwyn Studio 



Summary. Magnetic sound recording systems are being investigated for possible 
application by the motion picture industry. With limited current literature and the 
general nature of present industry discussions, certain peculiar requirements for 
studio use have not been taken into account, but are outlined here. The discussion 
represents the opinion of one studio's sound department based on the present state 
of developments and the information at hand, but is, of course, subject to modification 
as experience and additional information are acquired. 

It seems almost certain that some form of the magnetic methods 
of recording and reproducing sound can have an important value 
in many phases of motion picture sound recording. That their value 
can extend to the theater reproduction field as well seems probable 
but for present purposes no attempt will be made here to evaluate 
the use in this part of the field. 

Many groups are studying magnetic methods but the limited 
current literature and the discussions in general appear to be directed 
along lines which, while valuable in themselves, do not take into 
account certain peculiar requirements which are important to the 
studio use of recording media in picture production. While a new 
medium which may be a replacement for film may, because of its 
nature, require changes in existing technique, nevertheless these 
existing techniques should be studied to see how much could be 
salvaged by adapting the new processes to what we have rather 
than by taking the other point of view of trying to change everything 
to conform to present known forms of the magnetic medium. 

As a starting point, let us make a few assumptions as follows and 
then see what could be done with the magnetic methods: 

(1} Frequency response can be made at least equivalent to that of our present 
film . This must be qualified by the factors of signal-to-noise ratio and distortion, 
in other words, high-quality volume range. 

* Submitted Jan. 11, 1947. 
'* Sound Department, Metro-Goldwyn-Mayer Studios, Culver City, Calif. 


58 W. C. MILLER Vol 48, No. 1 

(2) The recording medium in the form of iron oxide or equivalent magnetic 
material can be used on a physical carrier having the same general characteristics 
as our present film base. 

(3) The present film velocity of 90 ft per min, or l l / 2 ft per sec, can be main- 

(4) Recording and reproducing heads can be physically adapted to existing 
film running apparatus. 

These assumptions will be discussed later and the probability of 
their being sound can be evaluated in terms of existing data and of 
design possibilities. However, if they are sound we can readily 
outline some of the immediate modifications which would seem de- 
sirable in the normal studio technical routine. 

All original recordings could be made on magnetic film with all 
the advantages of immediate monitoring of the recorded signal, 
direct playback, reuse of film previously used on discarded takes. 
In this connection it should be emphasized that the use of the photo- 
graphic printer and of the photographic developing processes are 
completely eliminated. While they have been brought to a good 
degree of control under optimum conditions, nevertheless they are 
constant contributary trouble factors in the complex chain of processes 
now necessary to produce a finished record. 

The magnetic film original record would then correspond to our 
present original film negative and would be treated with the same 
care afforded to the latter. Daily prints, editorial and rerecording 
reprints would be magnetically recorded from this magnetic film 

Using film as a carrier for the magnetic material would continue 
the use of key numbers, edge numbers, and sprocket holes for editorial 
identification, synchronization and measurement, using the identical 
equipment now in use and with which all studio personnel have 
become familiar. 

It is conceivable that had the magnetic development taken place 
a few years ago the motion picture industry might even have recom- 
mended the elimination of sprocket holes for sound film if some 
other suitable length-metering device had been developed. Now, 
however, the sole purpose of the sprocket holes is for driving and for 
general synchronization purposes, as all modern film running equip- 
ment uses some form of a constant speed drum device and filter sys- 
tem to maintain constant film speed at the optical center. All of 
this equipment now exists or is in the process of manufacture for new 


installations and it will put an insurmountable burden on any other 
form of physical carrier for the magnetic material to show why the 
present costly equipment should be discarded. 

In this connection also, all of the magnetic heads of the type which 
has both poles on the same side of the recording medium have to 
date been of such size that they can be mounted with little difficulty 
at some suitable place in the film path of each type of existing equip- 
ment. Not only this, but they can usually be mounted in addition 
to the present optical systems so that during a long transition period 
from photographic to magnetic methods, the existing equipment 
can run either kind of record interchangeably. 

Rerecording procedure would be much the same as at present, 
neglecting for the moment the plans already under way for automatic 
features in rerecording work. The many rerecording sound tracks 
would ultimately all be on the magnetic film but for a long time to 
come both photographic and magnetic records would be used inter- 
changeably to make full use of the great amount of sound library 
material which has been accumulated. Until some further develop- 
ment is made to utilize magnetic methods for the theater, the release 
tracks would continue on the existing photographic media. 

General editorial technique in the preparation of master and other 
rerecording sound tracks would remain virtually unchanged with one 
or two important exceptions. 

In the first place, the editor can no longer read the striations on 
the magnetic tracks. There can be no doubt that this is a dis- 
advantage. However, a modified type of Moviola device is already 
projected which will permit the editor to stop a track accurately 
at a precise point, and mark it for later splicing. Editorial personnel, 
given improved equipment of this kind, will undoubtedly develop 
cutting technique which will permit the full flexibility now enjoyed. 

Perhaps offsetting this disadvantage is the fact that dirt and 
scratches, which are so much of a noise hazard at present, will virtually 
disappear as a problem. All of the time and care now required to 
condition properly tracks and splices should be greatly reduced. 

In addition, methods will be developed to permit magnetic fading 
and elimination to supplant and replace the existing methods of 
painting or otherwise treating sections of track which require modi- 
fication. Plans for one such type of apparatus include a potenti- 
ometer arrangement which permits making fades or eliminations by 
listening trial until the proper length and character of fade is deter- 

60 W. C. MILLER Vol 48, No. l 

mined. Then current corresponding to the potentiometer and 
footage settings is automatically applied to modify the magnetic 
record by the precise predetermined amount. 

The choice of the film width to be used is a matter to be determined. 
At the MGM Studios the selection will undoubtedly be 17.5 mm. 
This has been of extraordinary value in the photographic form and 
there appears to be no good reason to change. The one change 
that may be recommended is to use 17.5 mm for negative instead 
of the two-edged use of 35 mm at present. The latter was adopted 
to make use of 35-mm developing equipment in the film laboratory, 
a requirement which no longer would have any bearing. 

There may be some discussion of the use of 16-mm film but in the 
writer's opinion the 17.5-mm film having sprocket holes of the 35-mm 
type on one edge only has the advantage of using the larger and more 
frequent holes for which all equipment in the studio is already sup- 

Returning to the assumptions previously made, perhaps a brief 
analysis of the various quality considerations will still further indicate 
that full development should be made to try to adapt the magnetic 
methods to the film carrier medium. However, it should be clearly 
understood that this does not in any way imply that the various 
forms of wire and magnetic tape, not on film, are improper for other 
kinds of uses for the magnetic methods. For home recordings, 
stenographic purposes, high-quality time delay devices for broad- 
casting, etc., the film medium is perhaps not the best. But for 
motion picture studio purposes it probably is. 

Quality considerations in the magnetic medium, in particular the 
oxide or equivalent tape or film, are in many respects the same as 
they are in our present photographic recording media. Certainly 
the end point is the same. We are looking for proper frequency 
response, absence of spurious harmonics and secondary effects, a 
minimum of noise. Also, both methods have certain inherent 
similarities such as variable response at various parts of the fre- 
quency spectrum, overload limits, etc. 

As an approach let us first consider that the so-called flat response 
is a kind of theoretical starting point from which we immediately 
have to deviate because of the characteristics of microphones and 
speaker systems and also because of the particular requirements 
which the final reproduction must meet. One very important aspect 
of such adjustments, and one which is much less commonly under- 


stood and recognized than it should be, is that sound reproduction 
for motion pictures is and should be much different than for radio, 
phonographic, or public address work. Without going into a detailed 
discussion of this problem, it is the desire merely to point out the 
difference in reproduced volume level and the presence factor required 
for pictures which has no counterpart in radio or phonograph work. 

In any case, this means adjustment of characteristics equalization 
at one place or another in the over-all system. In film work it 
happens that much of this equalization amounts to a reduction of 
low frequencies and to a reasonable extent the augmentation of high 
frequencies. The reduction of lows does little to the noise content 
if it is done properly. Among other things we use a pre- and post- 
equalization technique in film work whereby the highs are increased 
in the recording in conformity with the statistical probability of 
relative occurrence in various parts of the spectrum, and are then 
correspondingly decreased in reproduction. 

In magnetic work the pre- and post-equalization will apparently 
involve pre-equalization at low frequencies and the corresponding 
posting in reproduction. From the data available it would appear 
that it will be quite practicable to secure the proper over-all charac- 
teristic including microphone and speaker. 

Frequency response in the magnetic method depends upon several 
factors, notably film speed, pole piece separation and of course 
constant and uniform contact between the pole piece and magnetic 

It is certain that the contact problem is to be readily solved. A 
brief study of existing film paths will show this to be the case. 

Pole piece separation is quite analogous to recording and repro- 
ducing slit widths. In fact in many respects the magnetic tape 
methods may be considered to some extent the counterpart of a 
variable-density film sound track produced by a variable intensity- 
constant slit width method, with variation in what might be loosely 
called the magnetic density instead of variation in the density or 
transmission of a photographically produced record. 

With this comparison in mind, the problems of film velocity versus 
slit width should be susceptible to analysis on somewhat the same 
basis for the two methods. At a 90-ft per min (I 1 / ' 2 ft per sec) velocity 
we have found by experience that a reproducing slit 0.001 to 0.0012 
in. wide is satisfactory over the frequency range required. It would 
seem that the same reasoning can apply to the magnetic device. 

62 W. C. MILLER 

Present magnetic air gaps have certain fringing effects which, of 
course, are increasingly important at the higher frequencies. These 
will be minimized by design developments. In any case, they 
ultimately may quite possibly be no more serious than the diffraction 
and reflection effects we now have resulting from our attempts to 
pour a large amount of light through a very small slit formed by 
mechanical devices which are quite large relative to the light wave- 
length going through them. 

The extent of the frequency range required in motion picture work 
should be considered. It is very doubtful if frequencies above 
7500-8000 cps will be required for a very long time to come, if ever. 
The industry is fully aware of the fact that this range is limited but 
practical considerations over a number of years have all combined 
to produce what might almost be termed a standardized limited range. 
We need and want the closest practicable approach to perfection 
within this range but we can very safely discard everything above 
it for commercial purposes. It seems extremely unlikely that public 
tastes will be so affected by any use of frequency modulation or 
stereophonic recording as to require much modification of this re- 


This year of 1946, on July 24, marked 30 years of achievement in 
motion picture engineering for the Society of Motion Picture Engi- 
neers. The general growth, progress and achievement of our So- 
ciety has been described in a previous article by Hyndman and 
Maurer. 1 I thought you might be interested in a brief review of the 
accomplishments of your Society this year. 

Twenty-six new American Standards have been issued and five 
additional proposals have been submitted to Sectional Committee 
on Motion Pictures Z22 of the American Standards Association. 
The 26 American Standards have been referred by the ASA to the 
United Nations Standards Co-ordinating Committee [succeeded by 
International Organization for Standardization Ed.], the new in- 
ternational standardizing body. The ASA has proposed to the 
UNSCC that the Secretariat for Motion Pictures on international 
standards be located in the United States. In addition to the 
standards and proposals mentioned, three more proposals for 
standardization are now out to letter ballot of the Committee 
on Standards of the SMPE. You are all familiar with the American 
Standards Binder or book which your Society issued. This binder 
has already received much commendation from engineers and has 
been widely circulated as an authoritative reference. 

Revision of 35-Mm and 16-Mm Visual Test Films as recom- 
mended by the Joint SMPE-Research Council Committee has been 
completed by the Committee on Projection Practice of the SMPE. 
The initial or answer print of this new film will be previewed by the 
Joint Committee during this Convention. The Research Council 
of the academy of Motion Picture Arts and Sciences and the SMPE 
are now mutually co-operating on specifications for both sound and 
visual test films, in both 35-mm and 16-mm widths, to make unified 
recommendations and provide standard test films to industry. 

* Presented Oct. 21, 1946, at the opening luncheon of the Sixtieth Semiannual 
Convention in Hollywood. 

** President, Society of Motion Picture Engineers. 


In the past nine months our membership has grown to 2400, 
an increase of 425 new members since January 1. Five hundred 
new subscriptions to the JOURNAL have been received from colleges, 
engineering schools, libraries, and foreign film interests. The 
Executive Office Staff has been increased by the addition of an 
Engineering Secretary and Technical Stenographer, who have mate- 
rially accelerated the engineering and general service of the SMPE. 

As the result of a survey by the Committee on Motion Picture 
Instruction, arrangements are now in progress to establish Student 
Chapters of the SMPE at colleges and universities. Your Society 
has also created a Committee on Citations to honor and recognize 
the engineering and technical progress of individuals and companies 
that have contributed to the success of the motion picture industry. 
At the Banquet during the Convention you will hear more about this 
Committee's efforts. In honor of the Twentieth Anniversary of 
Sound in Motion Pictures, Warner Brothers Pictures, Inc., has ar- 
ranged with the Board of Governors of the Societies for an annual 
SMPE Samuel L. Warner Memorial Award to consist of a suitable 
Gold Medal and an appropriate certificate to be presented to any 
individual contributing an engineering or technical invention or im- 
provement which, in the opinion of an appointed Committee of the 
SMPE, is considered to be a recent advance in the art and a worthy 
asset to the motion picture industry. 

This year we have obtained an increase in Sustaining Memberships 
which to date amounts to approximately $14,000. These additional 
funds have permitted increases in our service, particularly when it 
is realized that the average member-cost to the Society has been 
over $14 per year for the past ten years. 

I have given you just a few brief facts in this motorcycle trip 
through the SMPE much more has been done. These accom- 
plishments result from the splendid co-operative work of the Execu- 
tive Office Staff, the Officers, Board of Governors, Committees, and 
Members. As your retiring President, I thank you, one and all; 
and as the engineer said to the fireman on the heavy freight, "Pour 
on the coal, boy, it's a long hard run ahead." Thanks a million. 


1 HYNDMAN, D. E., AND MAURER, J. A.: "The Past and Future Activities of 
the Society of Motion Picture Engineers," /. Soc. Mot. Pict. Eng., 47, 3 (Sept. 
1946), p. 212. 


The Journal Award for 1946 has been made to Ralph H. Talbot for 
paper entitled "The Projection Life of Film," which was published 
in the August 1945 issue of the JOURNAL of the Society of Motion 
Picture Engineers. This paper described several types of film 
damage and means by which each of the types can be minimized, or 
in some cases almost eliminated. An illuminated certificate was 
presented to Mr. Talbot in Hollywood, California, at the banquet held 
at the Hollywood-Roosevelt Hotel on the evening of October 23, 
1946, during the 60th Semiannual Convention of the Society. The 
Journal Award is presented each year to the author or authors of the 
most outstanding paper originally published in the JOURNAL during 
the preceding calendar year and treating some phase of motion pic- 
ture engineering. 

A native of Illinois, Mr. Talbot took his degree of Bachelor of 
Science in Chemical Engineering at the University of Illinois in 1925, 
following up with Master of Science degree in organic chemistry in 
1926. While there he was elected a member of three honor societies 
Sigma Xi, Phi Lambda Upsilon, and Phi Mu Alpha. 

Mr. Talbot joined the Eastman Kodak Company in 1927 where he 
was a member of the Synthetic Organic Division for a short time be- 
fore he left for the Tennessee Eastman Corporation, Kingsport, 
Tennessee, where he organized and equipped a control laboratory. 
He returned to Kodak Park in 1930 to join the Department of Manu- 
facturing Experiments. 

For some time Mr. Talbot 's chief work was on nitration of cellulose 
and the development of special solvent formulas which gave an im- 
proved film support for motion picture film. Later, he turned his 
attention to various problems on the projection of film, including wear 
and tear on the film during projection, scratch protection, and projec- 

* Recipient of 1946 Journal Award of the Society. 
** Eastman Kodak Company, Rochester, New York. 


66 E. K. CARVER 


tion quality in general. He has published several papers on these! 

Mr. Talbot is a musician of considerable ability. He has acted as 
conductor of an amateur concert orchestra for many years, in which 

Recipient of the SMPE Journal Award for 1946. 

he occasionally plays the trumpet. He is also a skillful fisherman, 
and trains and breeds setters for partridge hunting. He is an enthusi- 
astic amateur photographer, a past President of the Kodak Camera 
Club, and a member of the American Chemical Society. 


C. R. KEITH** 

Summary. The purpose, organization, and operation of the Committee on 
Motion Pictures are described, with particular reference to its relation to other stand- 
ards groups such as the SMPE Standards Committee and the Standards Committee 
of the Research Council of the Academy of Motion Picture Arts and Sciences. 

The formulation of standards for the motion picture industry has 
been recognized from the beginning as one of the most important 
functions of the Society of Motion Picture Engineers, and was one 
of the purposes for its organization. A large number of very valu- 
able standards have been worked out by its Standards Committee 
during the 30 years since the founding of the Society, and more re- 
cently a number of important standards have been adopted by the 
Standards Committee of the Research Council of the Academy of 
Motion Picture Arts and Sciences. With these two groups func- 
tioning in the motion picture field, it may well be asked why a third 
organization, the American Standards Association, is also needed. 

One of the important reasons for the existence of the ASA Com- 
mittee on Motion Pictures, Z22, is to provide the widest possible 
representation for approval of proposed standards. In addition to a 
wide representation from the motion picture industry, the Z22 Com- 
mittee includes representatives of numerous organizations not spe- 
cifically represented on the two other standardizing bodies. Among 
these organizations represented on the Z22 Committee are : 

Acoustical Society of America 

ASA Committee on Still Photography, Z38 

Bureau of Standards. 

Illuminating Engineering Society 

National Electrical Manufacturing Association 

Optical Society of America 

* Presented Oct. 23, 1946, at the SMPE Convention in Hollywood. 
** Chairman, Sectional Committee on Motion Pictures, Z22, American Stand- 
ards Association, New York. 


68 C. R. KEITH Vol 48, No. l 

Photographic Society of America 
Motion Picture Association of America 
U. S. Navy Department 
U. S. War Department 

Although motion pictures are a secondary interest to most of these 
organizations, they may in some cases have important interests 
which should be taken into account before a nationwide standard is 

Another purpose of the Z22 Committee is to co-ordinate motion 
picture standards with other American Standards. This avoids 
duplication or overlap between committees working in different 
fields. For example, the Z38 Committee on Still Photography has 
specified the same dimensions and perforations for 35-mm slide 
and microphones as have been established by the Z22 Committee 
for 35-mm motion picture film. Also the Z22 Committee has re- 
cently adopted for the motion picture field a definition of safety 
film prepared by the Committee on Still Photography, Z38. 

However, one of the most important reasons for the existence of 
the Z22 Committee is to co-ordinate American standards with for- 
eign standards. The world-wide distribution of American films 
and motion picture apparatus is, to a large extent, dependent upon 
the existence of the same basic dimensional standards in all countries. 

A good example of what happens when foreign standards are dif- 
ferent from American standards was the situation created a number 
of years ago when Germany adopted a standard for 16-mm sound 
films which would not permit interchange of American and German 
films or equipment. Although this difference in standards was un- 
intentional, it nevertheless caused a considerable amount of confu- 
sion and loss in the industry. Direct negotiations between the Ameri- 
can Standards Association and foreign standardizing bodies should 
prevent such occurrences in the future. 

The choice of organizations to be represented on Z22 is made 
jointly by the sponsor (the Society of Motion Picture Engineers) and 
the American Standards Association. Every effort is made to have 
broad representation without giving too much weight to any one 
group. Organizations represented are classified as producer, con- 
sumer, or general interest, and an approximately equal division is 
maintained among the three types. The choice of the individual 
who is to represent an organization is left to that organization. The 
chairman is elected by the committee. 


An important point in the committee procedure is that any mem- 
ber or group may propose a new standard or revision to an existing 
standard. Although most of the present standards were originally 
proposed and formulated by the SMPE, a number were originated 
by the Academy Research Council and some were taken from the 
work of the War Committee on Photography and Cinematography 

At least once every three years each standard is reconsidered and 
if any dissatisfaction is shown, it is investigated by a subcommittee 
of Z22 or referred to the SMPE or to the Academy as may be most 
appropriate for a particular case. When practical the report of the 
subcommittee, SMPE, or Academy is discussed at a meeting of the 
Z22 Committee, although because of the wide separation of members 
it is usually not feasible to hold a meeting more than once a year. 

All proposals are submitted for approval by letter ballot and con- 
sidered as approved only when receiving the affirmative vote of 
practically all members. All persons sending in negative votes are 
asked to give their reasons for disapproval. If in the opinion of the 
chairman the negative votes are justified, the proposal may be sub- 
mitted for a second vote with a transcript of the dissenting opinions. 

When approved by the Z22 Committee, the proposal goes to the 
SMPE Board of Governors for final approval from the sponsor, and 
from there to the ASA Standards Council. Having passed all of 
these hurdles, the proposal becomes an American Standard and 
after printing is available to any interested party in any part of the 



Years ago, when I was at college, I had to listen to many lectures 
I did not think I wanted to hear. Most of them turned out to be 
valuable lectures ; some were interesting; a few were even entertain- 
ing. I cannot forget, however, my profound distaste for the speaker 
who began with a recitation of historical data, hastily collected from 
the opening pages of the college catalogue, which his listeners had 
read, studied, and lived with for months. Such a recitation usually 
gave notice of a talk which spanned more time than its subject matter 

When Mr. Hyndman invited me to be here today, I gave some 
thought to what I might say about technical advances, standardiza- 
tion, and simplification in motion pictures. But those subjects are 
in the opening pages of your catalogue. Your technical deliberations 
will take you to heights which no layman could scale, and my chances 
of bringing you anything new in your own field are at absolute zero. 

I can stand off a bit, however, and speak in a general way of the 
importance of the work you are doing. 

The problems which face your members in these discussions, and 
in their daily search for technical betterment in the laboratory, are 
serious and challenging problems. They are of a character far re- 
moved from the ordinary conception of gay and light-hearted exist- 
ence in this much publicized community. Your meetings will con- 
stitute an example (and not an isolated example, either) of the serious, 
weary striving toward perfection which is the central inspiration of this 
great industry. In you, the outside world may see Hollywood at its 

You have assembled here at a time of great trouble in the affairs 

* Presented Oct. 21, 1946, at the opening luncheon of the Sixtieth Semi- 
annual Convention in Hollywood. 

* * Chairman of Board, Association of Motion Picture Producers, Inc., Holly- 


of humanity, and your meeting is by no means separate from the 
strivings of thoughtful men everywhere to bring a wool-gathering 
world back to mental stability. In the year that has passed since 
the glorious day of victory for united democratic peoples, a strange 
epidemic has swept the globe. Our own country has not escaped. 
At the moment of its greatest strength, it has been stricken with a 
creeping paralysis of frustration and indolence. 

The optimists may undertake to excuse this condition as a reflex of 
natural weariness after the supreme effort of the war. But surely 
after a year of floundering and failure, it is time to wonder whether 
the malady may not be more deep seated than that, and more danger- 
ous to our very existence. It is encouraging beyond words, there- 
fore, to see that our technical men, including yourselves, are not only 
dissatisfied with things as they are, but are undertaking to open new 
avenues of recovery and progress. 

The challenge to research is a continuing challenge of the ages. If 
in our present dilemma our public men are unable to find a- cure", 
perhaps the men of science can save us. Whether that be true or not, 
at least the scientific world must have the will to try. It is clearly an 
obligation of science that the momentum of the war years, which 
carried us so far on the road of destruction, shall not be lost as we 
turn to the building of a new world. 

In spite of all past progress, the making and exhibition of motion 
pictures still presents an important and fertile field for scientific 
research. I might dwell at length upon the contributions already 
made by your fine association, by the Research Council of the Acad- 
emy, and others. But this is hardly a time to point with pride. 
The important consideration is what we shall do with the future. 

It has become trite to say that the motion picture is the most potent 
human instrument of national and world understanding. But we 
must not forget that the screen will fulfill its destiny and reach its 
greatest power only in proportion to the fidelity of its portrayal of 
human life. The mirror it holds up to nature must be alive and 
untarnished, purged of corrosion and refined to a degree perhaps not 
yet dreamed of. 

For it is an axiom of the art of public entertainment that the public 
taste is fickle. Always the demand not merely the desire, but the 
demand is for something different and better. Today's audience 
would never be even moderately pleased with the crude mechanics of 
the Elizabethan theater. 

72 B. PRICE 

Unlike most of you, I am old enough to remember the earliest 
motion pictures. The patron paid a nickel for the privilege of sitting 
for a while in a highly uncomfortable chair, in a stuffy room, to see a 
flickering reproduction of the antics of amateurs, without spoken 
words and with no obligatto except the unceasing hammering of a 
piano badly out of tune, and the sputtering of a reel which broke or 
jumped the track with invariable regularity. We liked it, not so much 
because we experienced any sensation of beauty or inspiration, or 
even of entertainment, but because it was a novelty. I am very sure 
we would have tired of it soon enough, had not improvement held our 
interest. I even venture to say that if sound and color and other 
mechanical accomplishments had never been attained, the motion 
picture never would have survived except as a small side show of 
American life. 

Nor could the motion picture of the present day, with all of its 
miraculous qualities, expect to survive if research simply sat on its 
hands, surrendering to smugness and dreaming that perfection had 
been attained. The effective capture of the third dimension alone 
provides a goal worthy of the endeavor of the best minds among you. 
Instead of musing on the attainments of the past and present, we 
must have another kind of daydreaming. We must dream as Edison 
did, as Galileo did, as da Vinci did, and many others before and since. 

Much has been accomplished, but the plain truth is that the sum 
total is far too meager. In no way does it square with the opportunity. 
We must have in the industry a vastly more comprehensive research 
program, and I am happy to say that under the leadership of Eric 
Johnston preparations for such a program are in the making. What 
form it will take eventually cannot now be foreseen, since plans are 
far from complete ; but I feel justified in saying that already impor- 
tant and universal support for the project has become apparent 
throughout the industry. 

In this endeavor the industry greatly needs your continuing help, 
and that is why I am doubly happy to welcome you to this conven- 
tion. We greet you, not only merely as friends, but as friends in 
need, and sincerely wish you all success in the serious and significant 
work of your convention. 



Summary. Data are reported on the amount of light that can be projected to the 
screen with typical present-day carbon arc projection systems. Curves are presented 
which enable ready determination of illumination intensities on screens of various 
widths. Correlation is also made between the various systems and size of screen that 
can be illuminated to the brightness specified by the applicable ASA Standard. 

The history of the motion picture industry is documented with 
many new developments in the light sources used for projection. The 
individual developments in the carbon arc systems used for theater 
projection have been described in many papers published in previous 
issues of this JOURNAL. In addition, a paper 1 was presented in 1940 
which summarized the progress in the application of carbon arcs to 
motion picture projection from the beginnings of the industry up to 
that time. In the years subsequent to 1940, new developments in 
carbons, lamps, and optical systems have offered further substantial 

In view of these. improvements it is the purpose of this paper to 
present data on screen light obtained from measurements on typical 
present-day carbon arcs with various optical systems. Such a set of 
data is necessary for the determination of the projection system re- 
quired to illuminate adequately a motion picture screen of a given 
size. It is also of benefit in planning for new fields of projection. 

Projection Systems. The various units chosen as typical of 
present motion picture theater practice include low-intensity carbon 
arc combinations with reflector optical system, high-intensity arcs 
with nonrotating carbons and reflector systems, and high-intensity 
arcs with rotating carbons and condenser optical system. 

Mirrors 10 in. in diameter with a speed of f/2.3 and approximately 
4- and 24-in. working distances were utilized to obtain representative 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
** National Carbon Company, Inc., Fostoria, Ohio. 



information for low-intensity trim operation with 12-mm X 8-in. low- 
intensity positives and 8-mm X 8-in. low-intensity negative carbons. 

"One Kilowatt" direct-current arcs with 7-mm "Suprex" positive 
carbons and 6-mm "Orotip" C negatives and with //2. 5 mirrors hav- 
ing working distances of about 4-in. crater to mirror and 30-in. mirror 
to aperture were used as typical in this field. 

Mirrors 14 in. in diameter with a speed of //2.3 and with working 
distances of approximately 5 in. from the carbon crater to the mirror, 
and 34 in. from the mirror to the aperture were chosen as typical for 
simplified high-intensity lamps. The 8-mm X 12- or 14-in. "Suprex" 
positive and 7-mm X 9-in. "Orotip" C negative carbon trim, and the 
7-mm X 12- or 14-in. "Suprex" positive and 6-mm X 9-in. "Orotip" C 
negative carbons were considered in combination with such lamps. 

The rotating high-intensity carbon trims chosen were the 13. 6-mm 
X 22-in. regular high-intensity and super-high-intensity positives 
with Vie-in, or l / 2 X 9-in. "Orotip" negative carbons. Condenser 
lenses adjusted to give an//2.0 beam were employed as typical of good 
practice in this type of operation. The 6 1 / 4 -in. diameter rear element 
was placed approximately 3 in. from the carbon crater and the 7 1 /z-in- 
diameter front condenser was about 12 13 /i 6 in. from the film aperture. 

The film aperture considered was the standard 0.600 X 0.825 in. for 
35-mm film. Representative projection lenses designed for 35-mm 
film projection were utilized. 

Light Measurements. The measurements of screen illumination 
were based on the following general procedure. First of all, the arc 
lamp, film aperture, and projection lens were positioned as specified by 
the equipment manufacturers' instructions. By this means, the 
mirror-to-aperture (or condenser-to-aperture) distance was adjusted 
and the carbon crater-to-mirror (or crater-to-condenser) distance was 
set approximately. Optical alignment was achieved by placing a 
straight rod on the optical axis of the lamp, and by moving the aper- 
ture and projection lens so that the optical axes of the lamp, aperture, 
and lens all coincided. 

For convenience, most measurements were obtained using a short 
projection throw of about 12 ft and an illuminated screen area 2 to 3 ft 
in width. However, a number of confirming tests were made with 
projection throws as long as 65 ft and screen sizes as wide as 12 ft. 

Light intensities on the screen were obtained using accurately 
calibrated Weston Photronic cells equipped with Viscor filters. The 
cells were placed at five locations on the screen : one at the center, two 


on a horizontal line through the center and near the sides, and the 
other two near diagonally opposite corners of the illuminated screen 
area. The side and corner cells were spaced in from the boundaries of 
the lighted screen area by distances equal to five per cent of the hori- 
zontal and vertical dimensions of the lighted area. 

In order to obtain total lumens falling on the screen, it is necessary 
to have some method of averaging and weighting the values of in- 
tensity obtained at the five selected points. A satisfactorily close 
approximation to the average intensity has been found to be given by 
giving the center intensity a weight of two, the average of the sides a 
weight of two, and the average of the corners a weight of one. The 
average intensity so obtained is multiplied by the illuminated screen 
area to give total lumens. 

Wire screens of calibrated transmission placed over the front of the 
lamp, were found convenient to reduce the amount of light passing 
through the projection lens and to the screen. Some tests were car- 
ried out with no absorbing screens in order to check further on the 
accuracy of the transmission factors of the wire screens employed. 

Before any light measurements were made, the intensities at the 
sides and corners of the screen were balanced by tilting the mirror or 
by moving the condenser lenses vertically or horizontally. The dis- 
tribution of light on the screen, i. e., the ratio of intensity, sides-to- 
center, was adjusted by axial movement of the carbons in the mirror 
lamps, or by axial adjustment of the condenser lenses in the condenser 
lamps. In all cases, the positive carbon crater position, and the arc 
current and arc gap for the carbon trim were accurately maintained. 
The importance of close control of crater position and arc current to 
provide constant light on the screen has been described in a previous 
paper. 2 

Discussion of Data. Results of measurements of screen light are 
shown in Table 1 . The description of the carbon trim used, its oper- 
ating conditions and the lamp optics are specified in the first five 
columns of Table 1. 

Screen lumen values are next listed, both for a screen light distribu- 
tion ratio of 80 per cent side-to-center, and for the ratio resulting when 
the system is adjusted to give maximum intensity at the center of the 
screen. With each such adjustment, an //2.5 and an //2.0 pro- 
jection lens was employed. The//2.5 lens is untreated, and of 5.5 in. 
focal length, while the//2.0 lens, an example of a high-quality modern 
lens, is surf ace -treated and of 5.0 in. focal length. Similar measure- 


> dl 






1 1 


w ^ 9 




O "5 O O iO "5 C 

b- 50 (O 50 <D 

Vol 48, No. 1 




t^ O -H Tj< 

<o oo* o* 

"5 tC CO O* 


N <N <N c4 
^ ^ ^ ^ 

2 3 -2 .2 .2 .2 

Q s ^ u Q S P fe Q fe p g 

d -^ '? -^ a -S d Ja d .fi 

;s s ;s;s;s; S 

8 g 

d p .a a* <J a O 

05 : a : a : a w : a 

x '5 x '5 x '5 x '5 

8 S 


M 8 

a> 2 2 2 2 
2 5 S 2 2 S I J 

04 >-H 

Wi :** Wi U U U <M 


-< "x - 1 *H -" "M - 1 "K - "M te X 


b 1 

u 8 



a ?S 


* i 

fi 5 h 


a&I I 


4> *< 

2 ja >; 


; g 2 s 

J9 - 




2 ^ ^ t. r^ oo oo 

H V *> > ^O 


oo 0^ 


ments with other 4.5 and 5 in. E.F.f/2.0 lenses of various make were 
also made, but gave no significant difference in amount of screen light. 

The screen lumen values quoted are without allowance for shutters, 
filters, etc., since these more general light values can readily be cor- 
rected for the transmission of the particular accessories incorporated 
in a specific assembly of interest. The data in Table 1 show screen 
lumen values at maximum light ranging from 2500 to 21,500 and 
illustrate the wide range of possibilities offered by the various com- 
binations of lamps, carbons, and optical systems. It will be noted that 
the side-to-center screen distribution at maximum light is generally 60 
or 65 per cent. If a more uniform distribution of light is desired, this 
can be obtained at a sacrifice in intensity. Values of screen lumens 
are quoted at 80 per cent distribution as an example of a more uniform 
distribution and are approximately 10 to 15 per cent lower than maxi- 
mum values. 

The importance of adequate lens speed in utilizing the light pro- 
vided by the projection lamp is also illustrated by the data. The 
//2.0 treated lens gives approximately 50 to 60 per cent more light 
than the //2.5 untreated lens with the condenser lamp and 30 to 35 
per cent more with the mirror lamps. Much of the gain with the 
mirror systems results from the greater transmission of the treated 
lens. There is an additional gain with the condenser system because 
the//2.0 lens transmits light from the//2.0 condenser system which is 
not passed by the slower speed//2.5 lens. 

In order to compare the screen light intensity in motion picture 
theaters it is necessary to take into account such other factors as pro- 
jector shutter, heat filters, port glasses, draft glasses and screen size. 
Values of light intensity in foot-candles at the center of the screen are 
plotted for a range of screen widths in Figs. 1-4. These are based on 
the various projection systems and conditions of Table 1, and allowance 
has been made for : 

(1) A projector shutter of 50 per cent transmission, 

(2) A projection room port glass of 90 per cent transmission. 

The values obtained in a particular theater installation may differ 
from those reported here for numerous reasons, among which are the 
following : 

(I) Departure from the optical characteristics specified in Table 1. For 
example, many of the older lenses are of slower speed than//2.5. 

(2} The possible presence of absorptive factors in the optical train other than 
the ones assumed here. For instance, shutter transmission may be other than 



Vol 48, No. 1 


5.5*E.F. f.2.5 UNTREATED LENS- 


5.5*E.F. f : 2.5 UNTREATED LENS 

10 20 30 40 50 60 



O 20 




~5.0"E.F. f:2.0 TREATED LENS" 


5.0" E.F f:20 TREATED LENS 

10 20 30 40 50 60 10 20 30 40 50 60 


FIGS. 1, 2, 3, and 4. Light intensity 3 at center of various sized screens with typical 
carbon arc projection systems. 

Items l 
12-8-mm Low Intensity, 32 amp., 55 volts. 

5 8-7-mm 

'Suprex", 40 amp., 27.5 volts. 
'Suprex", 42 amp., 33 volts. 
'Suprex", 50 amp., 37 volts. 
'Suprex", 60 amp., 36 volts. 
'Suprex", 70 amp., 40 volts. 



13.6-mm- 7 /i6" High Intensity, 125 amp., 68 volts. 
13.6-mm-V2" High Intensity, 150 amp., 78 volts. 2 
13.6-mm- 1 /2 // Super-High Intensity, 170 amp., 75 volts. 2 


Refer to Table 1 for details on items. 

May require heat filter and result in 10 per cent decrease in width at given 


Foot-candle values assume 

(a) 50 per cent shutter transmission, 

(b) 90 per cent projection port glass transmission, 

(c) No film or filters other than port glass. 


50 per cent, a heat filter is sometimes employed, a draft glass is often used, and 
the present assumption with respect to the port glass may not apply. 

(5) Degree of cleanliness or misalignment of the optical system. 

(4) Departure from the specified operating conditions for the arc. 

Figs. 1 and 2 show the foot-candle intensities at the center of the 
screen under the above conditions for 80 per cent distribution and 
maximum light with the //2.5 untreated lens. Figs. 3 and 4 show 
similar data with the//2.0 treated lens. These curves show the screen 
widths that can be illuminated to intensities of 5 to 25 ft-c. The 
screen widths involved range from about 10 to 60 ft. It is perhaps 
worthy of note that in Fig. 2 with the//2.5 lens Item 8, the 150-amp 
arc, gives higher screen intensity than Item 9, the 170-amp arc, where- 
as this is not the case in the other three illustrations. The explanation 
for this anomaly rests on the relatively greater radiation of the 170- 
amp carbon at wide angles. It is necessary to use the higher speed of 
the//2.0 lens in order to obtain the higher light from the 170-amp arc. 

In order to ensure a sufficient screen brightness for proper viewing 
conditions, the American Standards Association Standard Z22.39- 
1944 has specified that "The brightness in the center of a screen for 
viewing 35-mm motion pictures shall be 10iJ foot-Lamberts when the 
projector is running with no film in the gate." 

The screen light intensities in Figs. 1 to 4 can be converted to screen 
brightness in foot-Lamberts by multiplication by the screen reflectiv- 
ity. This has been done using a screen reflectivity of 75 per cent 
and the resultant data have been used to plot Figs. 5-8. These 
block diagrams define the widths of screen which can be illuminated 
within the brightness limits of the ASA Standard just quoted by each 
of the nine projection systems with the screen distribution and pro- 
jection lens specified. It should be noted again that this is a general 
guide and variations from these data will occur under the conditions 
previously described. 

As an example of the use of the illustrations, Item 2, the "One Kilo- 
watt" direct-current system, is shown in Fig. 5 as being capable of 
illuminating screens 13 to 16.5 ft wide at 14 to 9 ft-L, respectively, 
with an//2.5 untreated lens and with an 80 per cent screen distribu- 
tion. If an //2.0 treated lens is substituted, larger screens of 15 to 
18 x /2 ft can be illuminated as shown in Fig. 7. If now this same 
system is adjusted for maximum intensity at the center of the screen 
then the widths become 14 x /2 to 18 ft with an//2.5 untreated (Fig. 6) 
and 16V2 to 21 ft with an//2.0 treated lens (Fig. 8). 



Vol 48, No. 1 


5.0 E.F. -f:2.0 TREATED 


20 30 40 10 20 




FIGS. 5, 6, 7, and 8. Size of screens capable of illumination to 9 to 14 ft-L 3 
at center with various projection systems. 

Items * 

1 12-8-mm Low Intensity, 32 amp., 55 volts. 

2 7-6-mm "Suprex", 40 amp., 27.5 volts. 

3 7-6-mm "Suprex", 42 amp., 33 volts. 

4 7-6-mm "Suprex", 50 amp., 37 volts. 

5 8-7-mm "Suprex", 60 amp., 36 volts. 

6 8-7-mm "Suprex", 70 amp., 40 volts. 

7 13.6-mm- 7 /i6 / " High Intensity, 125 amp., 68 volts. 

8 13.6-mm-V2" High Intensity, 150 amp., 78 volts 2 

9 13.6-mm-V2" Super-High Intensity, 170 amp., 75 volts 2 


1) Refer to Table 1 for details on items. 

2) May require heat filter and result in 10 per cent decrease in 
given brightness. 

(3) Foot-Lambert values assume 

(a) 50 per cent shutter transmission, 

b) 90 per cent projection port glass transmission, 

c) No film or filters other than port glass, 

(d) Diffusing screen with 75 per cent reflectivity. 

width at 


It is worthy of note that the nine typical systems described are 
capable of covering a screen width range of 10 to 39 ft to recommended 
brightness levels. 

Projection systems employing //2.0 condenser lenses (Items 8 and 
9, Table 1) sometimes produce an "in and out of focus" flutter of the 
film in the aperture, 3 so that heat filters or other means may be neces- 
sary to prevent such action. If filters of Aklo or Phosphate glass 4 are 
so used, the light values quoted in Table 1 will be reduced by approxi- 
mately 20 per cent and the screen widths in Fig. 1 to 8, inclusive, will 
be reduced by about 10 per cent, because of the light absorption by 
the heat filter. 

Although the discussion of screen illumination in this paper has 
been confined to systems commercially available at present, it should 
be kept in mind that experimental systems 5 are capable of delivering 
considerably more light than any of those described, and it is to be 
expected that the continued developments of higher brightness car- 
bons and improvements in optics will enable the achievement of still 
greater screen lumen values. 


1 KALB, W. C.: "Progress in Projection Lighting," /. Soc. Mot. Pict. Eng., 35, 
1 (July 1940), p. 17. 

2 ZAFFARANO, D. J., LOZIER, W. W., AND JOY, D. B.: "Improved Methods 
of Controlling Carbon Arc Position," /. Soc. Mot. Pict. Eng., 37, 5 (Npv. 1941), 
p. 485. 

3 CARVER, E. K., TALBOT, R. H., AND LOOMIS, H. A.: "Effect of High-In- 
tensity Arcs Upon 35-Mm Film Projection," /. Soc. Mot. Pict. Eng., 41, 1 (July 
1943), p. 69. 

ZAVESKY, R. J., NULL, M. R., AND LOZIER, W. W.: "Study of Radiant 
Energy at Motion Picture Film Aperture," /. Soc. Mot. Pict. Eng., 45, 2 (Aug. 
1945), p. 102. 

6 JONES, M. T., ZAVESKY, R. J., AND LOZIER, W. W.: "A New Carbon for In- 
creased Light in Studio and Theater Projection/' /. Soc. Mot. Pict. Eng., 45, 
6 (Dec. 1945), p. 229. 



The editors present for convenient reference a list of articles dealing -with subjects 
cognate to motion picture engineering published in a number of selected journals. 
Photostatic or microfilm copies of articles in magazines that are available may be 
obtained from The Library of Congress, Washington, D. C., or from the New York 
Public Library, New York, N. Y., at prevailing rates. 

American Cinematographer 

27, 11 (Nov. 1946) 
Mitchell Camera Company Opens New Plant for Expanded Production (p. 


Maurer Introduces New Professional 16-Mm Camera, (p. 402) 
Filmo "Electro" Camera for Time and Motion Study (p. 414) 
Kodachrome Introduced Commercial-Type 16-Mm (p. 421) 

British Kinematograph Society, Proceedings of the Theater Division (Session 

Electronics and the Kinema: 

1. Electricity and the Atom (p. 1) 

2. The Photoelectric Cell and the Thermionic 
Valve (p. 6) 

3. Electronic Aspects of Sound Reproduction 

(p. 10) 

4. The Cathode-Ray Tube (p. 17) 

5. Television (p. 22) 

The Thermionic Valve (p. 31) 

International Photographer 

18, 10 (Nov. 1946) 
Orthicon Television Camera Technical Data (p. 


New 16-Mm Lab Opens in Hollywood (Acme Film 
Laboratories, Inc.), (p. 22) 

International Projectionist 

21, 11 (Nov. 1946) 

Electronic Aspects of Sound Systems (p. 5) 
Incandescent Lamps for Film Projection (p. 12) 
Basic Radio and Television Course, Pt. 27 

Superheterodyne Trouble-Shooting Procedures 

(P. 20) 
Projection Rectifier Tube Data (p. 24) 










Physical Society, Proceedings 

58, (Sept. 1946) 
The Performance of Aircraft Camera Lenses (p. E. W. H. SELWYN AND 

493) J. L. TEARLE 

Optical Problems of the Rotating Prism Cine- 
matograph Projector (p. 598) J. KUDAR 
Radio News 

36, 6 (Dec. 1946) 
Sound Amplification by Air-Stream Modulation 

(p. 39) J. McQuAY 



Lloyd Thompson, of the Calvin Company, Kansas City, Mo., and E. J. Weinke, 
of Motiograph, Chicago, were guest speakers at the meeting of the Midwest 
Section of the Society in Chicago on Dec. 12, 1946. Speaking on "Quantity 
Production of Kodachrome Prints," Mr. Thompson described a projection mat 
contact step printer for making a limited number of prints, and a continuous 
"Multimatic" printer for obtaining effects by use of a mat. 

Mr. Thompson also discussed the drum printer used for color control and check 
of prints, and the edge-numbering machine developed by the Calvin Company. 

Mr. Weinke spoke briefly of the 50th anniversary of Motiograph and described 
their new projector. Of particular interest to the members and guests present 
were the double concentric barrel shutter, grease-sealed bearings, gun-latch gate 
opening, and measured adjustable shoe pressure. 

The meeting concluded with a showing of a motion picture supplied by the 
Calvin Company, and examination of the projector head. 


The sixteenth annual meeting of the Inter-Society Color Council will be held 
on Feb. 24-25, 1947, at the Hotel Pennsylvania and Hotel Commodore, 
New York, and members of the SMPE are cordially invited to attend any session 
of interest. The Secretary of the Council advises that the meeting is planned to 
follow that of the Optical Society and to coincide with that of the Technical 
Association of the Pulp and Paper Industry. Complete and final programs are 
available from Dorothy Nickerson, Secretary, P. O. Box 155, Benjamin Franklin 
Station, Washington 4, D. C. In brief, the program on February 24, at the 
Pennsylvania Hotel, beginning 9:30 A.M., will consider color terms, color aptitude 
test, color blindness test, illuminating and viewing conditions for colorimetry, 
and the illuminant in textile color matching. 

On February 25, at the Commodore Hotel, starting at 9:30 A.M.> papers will be 
presented on "The Paper Man's Interest in Color," colorimetric standardization 
in industry, and color-order systems. At 2:00 P.M., topics on spectrophotometry 


ICI standard observer and co-ordinate system, inter-relation of color specifications, 
and color engineering will be discussed. 

We are grieved to announce the deaths of Hastings W. Baker, Asso- 
ciate member of the Society, on October 25, 1946, in New York, N. Y., 
and Harry L. Denton, Associate member of the Society, on December 
14, 1946, in Chicago. 


Motion Picture Engineer Wanted. Applicant must be fully experienced 
in all phases of motion picture production; capable of managing new 
motion picture studio in Cairo, Egypt. Apply direct to Teca Corporation, 
220 West 42d St., New York 18, W. Y. Replies will be held in confi- 


Chicago, Illinois 

April 21-25, 1947 

Officers in Charge 

LOREN L. RYDER ............................ President 

DONALD E. HYNDMAN ....................... Past-President 

EARL I. SPONABLE .......................... Executive Vice-P resident 

JOHN A. MAURER ........................... Engineering Vice-P resident 

M. R. BOYER .............................. Financial Vice-President 

C. R. KEITH ............................... Editorial Vice-President 

W. C. KUNZMANN .......................... Convention Vice-President 

G. T. LORANCE .............................. Secretary 

E. A. BERTRAM ............................. Treasurer 

General Office, New York 
BOYCE NEMEC .............................. Engineering Secretary 

HARRY SMITH, JR ........................... Executive Secretary 

Directory of Committee Chairmen 

Midwest Section and Local Arrangements ..... A. SHAPIRO, Chairman 

Papers Committee .......................... GORDON A. CHAMBERS, Chairman 

R. T. VANNIMAN, Vice-Chairman 

HERBERT B ARNETT, Wee- Chairman 

N. L. SIMMONS, Vice-Chairman 

Publicity Committee ........................ HAROLD DESFOR, Chairman, 

assisted by LEONARD BIDWELL, 
Registration and Information v ; ............... W. C. KUNZMANN, Chairman, 

assisted by E. R. GEIB, G. W. 



Luncheon and Banquet W. C. DEVRY, Chairman 

Hotel and Transportation H. A. WITT, Chairman, assisted 

by C. H. STONE 
Membership and Subscription Committee 

(Midwest Section) TOM RESS, Chairman 

Ladies Reception Committee Hostess MRS. A. SHAPIRO 

Projection Program Committee 35-mm S. A. LUKES, Chairman, assisted 

by Members Chicago Projec- 
tionists Local 110 
16-mm H. WILSON, Chairman 


The management of The Drake, located at Lake Shore Drive and Upper 
Michigan Ave., Chicago 11, Illinois, Convention Headquarters, extends SMPE 
members and guests the following per diem room rates, European plan: 

Room with bath, one person $4 . 55-5 . 50 

Room with bath, two persons, twin beds $7.50-8.50-9.00-10.00-12.00 

Parlor suites with connecting bedrooms, two persons. $18 . 00-20 . 00-22 . 00-25 . 00 

Note. Room accommodations must be booked early and direct with W. N- 
Cowan, Front Office Manager, The Drake, prior to April 15. When making 
reservations be sure to advise Mr. Cowan that you are attending the SMPE 61st 
Semiannual Convention. No rooms will be assured or guaranteed at The Drake 
unless confirmed. 


With travel conditions still not normal, the Eastern and West Coast members 
who are contemplating attending the 61st Semiannual Convention should consult 
their local railroad, Pullman and plane agents regarding effective schedules and 
rates at least 30 days prior to your departure. 


The Convention Registration Headquarters will be located in the French Room 
Foyer of The Drake. Members and guests are expected to register. The fee is 
used to help defray the Convention expenses. 


Members and others who are contemplating the presentation of papers at the 
Chicago Convention can greatly assist the Papers Committee in the early schedul- 
ing and assembly of the program by mailing in the title of paper, name of the 
author, and an abstract to the Papers Committee Chairman, or to the Society's 
offices in the Hotel Pennsylvania, New York, not later than March 15. Complete 
manuscripts must be received by April 7 to be included in the final program. 
Your co-operation in this regard is solicited. 

The Convention business and technical sessions will be held in the Grand Ball- 
room located on the lobby floor of the hotel. 



The usual Get-Together Luncheon will be held in Gold Coast Room on Monday, 
April 21, at 12: 30 P.M. 

The luncheon program and eminent guest speakers will be announced in later 
bulletins. Guaranteed seating at the luncheon will be assured only if tickets are 
procured prior to 11:00 a.m. on April 21. Assist the Committee and hotel in pro- 
viding accommodations by complying with this request. 


The SMPE 61st Semiannual Banquet and social get-together will be held in the 
palatial Gold Coast Room of The Drake on Wednesday evening, April 23, at 8:00 
P.M. (Dress optional.) 

Banquet tickets should be procured and tables reserved at the Registration 
Headquarters prior to noon on April 23. The Banquet program will be announced 
in later bulletins. 

Luncheon and Banquet tickets may be procured in advance of the dates of these 
functions through W. C. DeVry, Chairman of the Luncheon and Banquet Com- 
mittee, located in Chicago, or through W. C. Kunzmann, Convention Vice- 
President, who will be at The Drake several days prior to the opening date. 

Note. All checks or money orders issued for registration fee and luncheon or 
banquet tickets should be made payable to W. C. Kunzmann, Convention Vice- 
President, and not to the Society. 


Ladies attending the Convention should register with Mrs. A. Shapiro, the 
hostess, and members of her Committee in their headquarters, Parlor //, which is 
adjacent to the Grand Ballroom where the Convention sessions will be held. 

Ladies' entertainment program will be announced later by the Ladies Com- 


Convention recreational program will be announced later by the Local Arrange- 
ments Committee. Consult the hotel bulletin board or Registration Head- 
quarters for other local amusements available in Chicago during the Convention 


Convention identification cards will be honored through the courtesy of the 
Balaban and Katz Corporation at the following deluxe theaters located in the 
Loop, namely: Chicago, State Lake, and United Artists Theaters. 

The H. and E. Balaban Corporation extends their courtesy and will honor these 
cards at their Esquire Theater located in the immediate vicinity of The Drake 

RKO Theaters (Chicago Division) extends their courtesy of honoring the Con- 
vention identification cards at their deluxe RKO Palace and Grand Theaters, 
located in the Loop. 



Monday, April 21, 1947 

Open Morning. 
9:30 a.m. French Room Foyer: Registration. Advance sale of Luncheon and 

Banquet tickets. 

12:30 p.m. Gold Coast Room: Get-Together Luncheon (Speakers). 
2: 00 p.m. Grand Ballroom: Business and Technical Session. 
8: 00 p.m. Grand Ballroom: Evening Session. 

Tuesday, April 22, 1947 

9:30 a.m. French Room Foyer: Registration. Advance sale of Banquet 


10:00 a.m. Morning Session: Location to be announced later. 
2: 00 p.m. Grand Ballroom. Afternoon Session. 
Open Evening. 

Wednesday, April 23, 1947 

9:30 a.m. French Room Foyer: Registration. Advance sale of Banquet 

10: 00a.m. Morning Session: Location to be announced later. 

Open Afternoon. 

8: 00 p.m. Gold Coast Room: SMPE 61st Semiannual Banquet and evening 
for social get-together will be held in the palatial Gold Coast Room 
(dancing and entertainment). The program for this evening will 
be announced later by the Banquet Committee. Tables may be 
reserved at the Registration Headquarters prior to noon on April 

Note: The Registration Headquarters will be open on this afternoon for those 
desiring to make final arrangements for the Banquet. 

Thursday, April 24, 1947 

Open Morning. 

2 : 00 p.m. Grand Ballroom: Afternoon Session. 
8:00 p.m. Grand Ballroom: Evening Session. 

Friday, April 25, 1947 

10:00 a.m. Grand Ballroom: Morning Session. 
2: 00 p.m. Grand Ballroom: Afternoon Session. Adjournment of the 61st 

Semiannual Convention. 

Note. All sessions during the five-day Convention will open with an interesting 
motion picture short. 



Book your room accommodations early and direct with W. N. Cowan, Front 
Office Manager, The Drake, Chicago, Illinois. All reservations are subject to 
cancellation prior to April 10. 

Co-operate with the Luncheon and Banquet Committee by procuring tickets 
well in advance of the dates for these functions, so that hotel arrangements can be 
made accordingly. 

This is a tentative schedule and is subject to change. 

Convention Vice- President 

\ The second group of American Standards on Motion Pictures 

printed in the new distinctive S 1 /^ X 11 -in. format is now available for 
inclusion in the SMPE Standards Binder shown above. These six 
additional Standards, published in the September 1946 JOURNAL, 
are supplied as a service to motion picture engineers and industrial 
librarians who must maintain files of American Motion Picture Standards 
for easy and ready reference. 

As a further service, purchasers of this Binder are notified by the 
Society when new Standards or revisions thereof are published. All 
American Motion Picture Standards published in the future will be 
punched to fit this Binder. 

The price of the SMPE Standards Binder with a complete set of all 
26 current American Motion Picture Standards is only $5.10.* 
Send check, money order, or company purchase order now to the 
Society of Motion Picture Engineers, Hotel Pennsylvania, New York 1 , 
N. Y. 

* Add 50 cents for postage and special packing if mailed outside the United States 
to New York City address, add 2 per cent Sales Tax. 

If mailed 


Vol 48 FEBRUARY 1947 No. 2 



Film Projectors for Television R. V. LITTLE, JR. 93 

Studio Production with Two-Color Bipack Motion Pic- 
ture Film J. W. BOYLE AND B. BERG 111 

The Practical Problems of 16-Mm Sound A. JACOBS 116 

International Motion Picture Standards 

D. E. HYNDMAN 126 

Light Control by Polarization and the Application of 
Polarizers to the Stereoscopic Process 

J. A. NORLING 129 

Preliminary Report of Research Council Photocell Sub- 
committee L. T. GOLDSMITH 145 

A Be Luxe Film Recording Machine M. E. COLLINS 148 

A New 16-Mm Professional Camera F. F. BAKER 157 

Report of Sectional Committee on Motion Pictures, Z22 163 

Reports of SMPE Committees : 

Report of the Committee on Preservation of Film 167 

Report of the Committee on Standards 170 

Report of the Committee on Theater Engineering, 

Construction, and Operation 173 

61st Semiannual Convention 176 

Society Announcements 180 

righted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 






(Board Under Organization) 
** President: LOREN L. RYDER, 

5451 Marathon St., Hollywood 38. 
**Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
** Executive Vice-President: EARL I. SPONABLE, 

460 West 54th St., New York 19. 
^Engineering Vice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial Vice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
* 'Financial Vice-President: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
^Treasurer: E. A. BERTRAM, 
850 Tenth Ave., New York 19. 

**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 5451 Marathon St., Hollywood 38. 
*fjAMES FRANK, JR., 356 West 44th St., New York 18. 

*JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*JA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
*WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

*Term expires December 31, 1947. tChairman, Atlantic Coast Section 
**Term expires December 31, 1948. tChairman, Midwest Section. 
"Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 

their annual membership dues; single copies, $1.25. Order from the Society at address above. 

A discount of ten per cent is allowed to accredited agencies on orders for subscriptions 

and single copies. 
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 
General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 
Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., 
urder the Act of March 3, 1879. 


Vol 48 FEBRUARY 1947 No. 2 


Summary. Television will make wide use of 35-mm and 16-mm motion picture 
film. The method of televising motion pictures using the storage-type pickup device 
is described. Theater and television projection practice are compared and methods 
of meeting proposed RMA Television Standards are discussed. Recently designed 
16-mm and 35-mm RCA television projectors are described in detail. 

Television, the new vehicle for providing entertainment in the 
home, relies on three main sources of program material. These are : 
studio . productions of plays, interviews, and related material; field 
pickups of such events as boxing, tennis, baseball, and other on-the- 
spot items of general interest; and motion picture film subjects. A 
well-planned program will endeavor to use all of these means, pos- 
sibly in the same broadcast period, to achieve the smoothest and most 
pleasing continuity obtainable for the entertainment of the home 
audience. It is also quite evident that for economic reasons the 
smaller station may, initially at least, lean more heavily on motion 
picture film, either of the standard variety or in the form of syndicated 
films of television studio productions as a source of program. 

For such reasons it may be of interest to outline the developments 
and general problems peculiar to television motion picture projector 
systems. Motion picture films are reproduced in a television system 
by projecting the motion picture image upon the photosensitive sur- 
face of a pickup tube in the television camera. The video signal is 
generated at this point by a process of scanning the motion picture 
image electrically to produce an electrical or television signal. 

There are several possible projector systems for carrying out this 
transfer of optical information into a video or picture signal. They 
can be divided into two main classifications, using either continuous 

* Presented Oct. 24, 1946, at the SMPE Convention in Hollywood. 
* * RCA Victor Division, Radio Corporation of America, Camden, N. J. 


94 R. V. LITTLE, JR. Vol 48, No. 2 

or intermittent film motion in -the projector. At RCA we have con- 
centrated our efforts on the "intermittent" type of film projector. 
In this system it is essential that the television pickup tube have 
"storage" or the ability to retain a photoelectric charge image corre- 
sponding to the illuminated picture pattern projected on its light- 
sensitivity surface by the action of a light-pulse applied during those 
intervals when the film is stationary in the film-gate. The "Icono- 
scope," 1 a tube used for this purpose, has this property of storage, 
which allows the picture information to be projected, stored, and 
then utilized to form an electrical picture signal by television scan- 
ning during the time intervals when the tube is in complete darkness. 

The scanning process consists of a systematic sweep from left to 
right and from top to bottom of the photosensitive area by an elec- 
tron beam followed by the return of the beam to the starting position. 
The time required for the beam to return to the top of the raster after 
completing a vertical scan is called the retrace time; during this in- 
terval the beam and the system are cut off by the use of a vertical 
blanking pulse. It is during this blanking time that the film is at 
rest in the projector and the picture is flashed on the mosaic by a high- 
intensity light pulse. The stored picture is then scanned in complete 
darkness by the electron beam during the succeeding vertical scanning 

With this over-all preview of the fundamentals of operation we can 
now examine in more detail the various points involved in inter- 
mittent-type motion picture television projectors. 

Theater Projectors. Motion picture practice has standardized 
on a projection rate of 24 frames per sec for both 16-mm and 35-mm 
sound films. The method of projection is such that the projected 
light is interrupted twice per frame; once to permit pull-down to the 
successive frame and once during frame time to give an additional 
interruption to the picture image. This double showing of each frame 
reduces the sensation of flicker to the eye by doubling the repetition 
rate of the flicker. 2 Since each picture is actually seen twice, the 
flicker or field frequency is 48 times per sec, high enough to give the 
illusion of no flicker at all at the picture brightness normally employed 
in theaters. 

Television. television operating standards have been proposed 
by the Radio Manufacturers Association for adoption by the in- 
dustry and by the Federal Communications Commission. 

One of the recommendations of the RMA is that of operating a 


television system so that it can be tied in with the 60-cycle power 
lines which are widely used in America. Such television operation 
minimizes the effects of hum-pickup and makes electrical filtering at 
both the transmitter and the receivers considerably easier and more 
economical. The repetition frequency of television pictures is 
therefore 60 fields per sec, well above the perceptible flicker rate. 

The use of interlacing, 3 which is a system of transmitting all the 
odd-numbered scanning line detail in one field followed by all the 
even-numbered scanning line detail in the next field, produces one 
completely scanned picture in one frame or 1 /so sec. This gives an ef- 
fect which is quite analogous to the action of the shutter in stand- 
ard theater projectors. Scanning begins in the upper left-hand cor- 
ner and proceeds in parallel lines until the scanning beam reaches the 
bottom of the raster. The even lines have now been scanned and the 
beam returns to scan the odd lines. The present system scans 262 1 / 2 
parallel lines during one field and 262y 2 alternate lines during the 
successive field, to form a 525-line raster at the rate of 30 frames per 
sec. This gives a repetition rate of 60 fields per sec, which is high 
enough to eliminate flicker without requiring the prohibitively wide 
frequency channel necessary for other methods of arriving at the 
same result. 

However, the adoption of standards giving a scanning of 60 fields 
or 30 complete frames per sec, using standard 24 frame-per-sec moving 
picture has required the development of special television-type motion 
picture projectors. 

Picture Fields and Frames. Certain fundamental definitions 
can be introduced in order to develop a useful approach to an under- 
standing of the television processes which are taking place when film 
transmissions are being made. Terms which are closely analogous in 
motion pictures and in television can be used to advantage. By using 
the term "field" to designate each interval in which motion picture or 
television information is projected, we can say that theater motion 
picture projections are at a rate of 48 fields from 24 frames per sec, 
and television images are made up of 60 fields interlaced to become 
30 frames per sec. 

Considerable time is required between frames to move the film 
past the aperture from one frame to the next; during this interval 
the light is cut off by the shutter whose additional function is to 
interrupt the light once during the frame time. We show this di- 



Vol48 No. 2 

Picture Sequence. In the sequence diagram of Fig. 1, the first 
block indicates showing time; the next shaded portion indicates 
shutter time ; the third shows time ; and the fourth, shutter time to 










- 25V. 


- 25% 






FIG. 1. Thirty -five millimeter theater projector time cycle. 

complete one frame. The second shutter time covers the film pull- 
down interval. Fields and frames are designated and the relative 
intervals for 35-mm practice are shown. In television there is also a 
function comparable to pull-down which must be completed between 
fields ; this is the return of the scanning beam from the bottom of one 







FltM FRAME K>0\^SEC. - 

. ... 





I I I 

i ' ' 

__ , ^ 

5 /* 1 *.. 


FIG. 2. Time-cycle comparison. 

scanning raster to the top of the next scanning raster. An electrical 
blanking signal is used during this interval to make the picture beam 
blank or cut off so as to allow for an invisible retrace of the scanning 
beam. The signal used is called vertical blanking and occurs at the end 
of each vertical scanning field. 

Feb. 1947 



Time-Cycle Comparison. The terminology in Fig. 2 is similar 
to that used in Fig. 1 ; the difference in the proportion of showing to 
blanking is noticed at once. A change has been made in the repre- 
sentation of the theater projector cycle, removing the shutter in 
order to permit maximum showing time. Television scanning is char- 
acterized by using a nominal five per cent of the total available time 
for blanking between fields. The remainder of the time is used for 
scanning or showing. 

The problem is to obtain picture information for the television 
system at a repetition rate of 60 times per sec in order to have infor- 
mation for each television field, and still run the film at 24 frames a 






JAN 22, 1946 



FIG. 3. Detail of proposed RMA television signal. 

We can see that the scanning intervals of the television system do 
not occur in such a manner as to give uniform picture information 
from the film to the television system. Scanning times occur in some 
cases during pull-down so that the picture information would change 
during a scanning and hence give the equivalent of travel ghosts. 
Pull-down requires such a long interval that it is impossible to use a 
conventional projector and have the required information available 
for each scanning. 

This alternative suggests itself: the television system can obtain 
video information during blanking by the storage principle. The 
Iconoscope allows the picture information to be supplied during the 
interval of blanking, stored as an electronic image, and scanned dur- 
ing periods of darkness. Therefore, methods must be devised to 
have a stationary picture available for every television field. 



Vol 48, No. 2 




Proposed RMA Signal. A single television field is shown in 
Fig. 3 as taken from the proposed RMA standard signal recom- 
mendations. It illustrates the design requirements on television 
showing time. 

The interval designated between bottom and top of picture is the 
vertical blanking time and is the time between scanning fields in which 
we must expose the television camera. The duration is shown as five 
per cent with a plus tolerance of three. 

Television Projector Time Cycle. Examination of this chart, 
line (A), shows two standard 35-mm picture frames each of 
x /24 sec duration, with each frame represented as a 360-deg cycle; 

720 RPM 


FIG. 5. Thirty-five millimeter film projector inter- 
mittent mechanism. 

from this we see a pull-down time indicated as 90 deg, leaving the 
balance as showing time, if we ignore standard shutters in this dis- 

In this chart, television fields with five per cent blanking have been 
added to scale. These blanking intervals must occur during pro- 
jector showing time intervals. The most important thing to point 
out here is the extremely short time interval between television fields, 
and the impossibility of a fast enough pull-down to accommodate 
the television system. Let us see how we can circumvent these prac- 
tical mechanical limitations. If we use the Iconoscope we can store 
a picture during the intervals of vertical blanking and scan the picture 
in complete darkness. 

Two possible methods of obtaining the proper showing time are 
charted. In line (B) the first showing interval can be shortened to 

100 R. V. LITTLE, JR. Vol 48, No. 2 

accommodate two blanking intervals for the projection of the first 
frame, and the second frame can be held for a longer time to accom- 
modate three blankings as indicated. In such a manner two ex- 
posures are made of one frame and three of the successive frame. 
Thereby we have made five television fields out of two frames of 
J /24 sec each. This gives us 60 television fields or 30 television frames 
per sec from film running at 24 frames per sec. This 2: 3 ratio of pic- 
ture projection, a very clever piece of trickery, is described in U. S. 
Patent 2,082,093, A. V. Bedford of RCA Laboratories, Princeton, 
*N. J. Light pulses for the Iconoscope are produced by a rotating 
shutter properly phased, with the television* system using a high- 
intensity light source. 

The other method shown in line (C) charts conditions with a very 
short pull-down time interval. If this is made approximately 50 deg as 
indicated, it allows two showings to be centered in one frame and three 
showings in the successive frame without resorting to any change in 
the time ratio of the intermittent mechanism from frame to frame. 
U. S. Patent 2,303,960, Stuart Seeley, RCA Licensee Laboratories, 
describes this alternative method for television of film projector 

The design of a 35-mm television projector with a fast pull-down 
(such as 50 deg) does not appear practicable because cutting the 
allowable time in half increases the acceleration forces by four times. 
These forces would exceed the elastic limit of the film ; the mass of the 
film in this case represents the major part of the load. Therefore, 
the 2:3 ratio intermittent represents a good solution to the problem. 
,35-Mm Intermittent Mechanism. This type of intermittent 
mechanism is used in the Brenkert BX80 theater projector which 
is being built by the Brenkert Light Projection Company for the 
RCA Victor Division. The standard theater Geneva movement is 
shown functionally in Fig. 5. A driveshaft turns the cam, with its 
single drivepin, at 24 rps; each revolution of the cam turns the four- 
point star wheel 90 deg and the picture moves one frame. The tele- 
vision intermittent designed for the BT90 projector is shown with a 
special cam divided in the ratio of 2 : 3 and driven at a reduced speed 
of 12 rps to maintain 24 rps at the sprocket shaft. The star now has 
three points to give the faster pull-down necessary because the cam 
pin speed has been halved. The sprocket has also been modified to 
have 12 teeth instead of 16. Since the angular rotation has increased 
to 120 deg, the film travel is maintained at the same rate as 

Feb. 1947 



previously used; i.e., four sprocket hole's to advance the picture 
one frame. 

16-Mm Intermittent Mechanism. Our 16-mm projector inter- 
mittent problem (Fig. 6) has been solved by increasing the nominal 
65-deg pull-down, of the RCA PG201 Projector, to approximately 45 
deg to accommodate the necessary picture exposures in the manner 
shown in line (C) of the time-cycle chart of Fig. 4. The designer, in an 
ingenious solution, has applied elliptical gears which are interchange- 
able with the existing spur gears. In effect the gear ratio is variable 



FIG. 6. Sixteen-millimeter film projector intermittent mechanism. 

so as to give an almost two-to-one speed change which is sufficient to 
make the pull-down 45 deg. The pull-down action is phased with the 
fast half -cycle of the elliptical gears so that the propelling motion is 
then the product of the normal cam action and the elliptical gear 
action. The result is a portion of a sine squared motion and very 
well suited for film advancing mechanisms. 4 The time gained on the 
pull-down stroke results in a retarded return stroke which reduces the 
strain and vibration in the mechanism. 

Light Source. Design of the intermittent mechanism repre- 
sents the solution to the first of three projector functions peculiar to 
television. The second problem is the light source and the method 
of accurately timing the duration and repetition of projected light. 

102 R. V. LITTLE, JR. Vol 48, No. 2 

An adequate light source for the Iconoscope must be capable of pro- 
ducing approximately 40 ft-c average illumination on the mosaic with 
no film in the machine. The duration of projection time must be five 
per cent or less with a repetition rate of 60 times per sec. 

There are two methods of meeting the light requirements : first, an 
adequate light source with a shutter can be made to give accurate 
timing of the projection interval; second, a type of light source which 
can provide the correct illumination by switching this source on at the 
proper instant and for the correct exposure duration. The first 
method has been used in previous television projectors and is the 
one used in our 16-mm television projector because of its simplicity 
and low cost. The second type of light source requires a lamp which 
can have its illumination cycle instantaneously controlled. Until very 
recently it has not been possible to obtain a practical source having 
the control, the light intensity, and life for this purpose. 

The shutter for the 16-mm projector is located where the cross 
section of the light beam to be interrupted is small compared with the 
shutter opening used ; by this method we have a fast opening and 
. closing and a considerable region of full opening time. The shutter 
is located immediately behind the aperture plate so that light and 
associated heat are on the gate only during the actual exposure in- 

Nevertheless, a light source operated by an electronic switch would 
be an ideal solution ; the short duty cycle of five per cent would con- 
serve power, and greatly reduce the heat in the projector mechanism 
and film. It is certainly logical to turn the light on when it is needed 
rather than to keep it on continuously and waste 95 per cent to ob- 
tain the five per cent pulse by a mechanical shutter. 

Early experimenters attempted to modulate a carbon-arc source 
with little success because of the glow retained in the incandescence 
of the arc crater. RCA has been experimenting in collaboration with 
Edgerton, using gaseous discharge lamps for this purpose for the past 
several years. Some degree of success has been obtained. A recent 
General Electric announcement has made public a successful system 
of pulsing a low-pressure xenon lamp using radar keying technique. 

RCA is planning to adopt this pulsed-light source for the 35-mm 
television projector. This will make possible many projector simpli- 
fications. The problem of designing and driving a 3600-rpm shutter 
has always been a difficult mechanical one. Without this shutter 
load the projector can be driven by means of sound head; the 

Feb. 1947 




[8% RMA MAX. 


conventional arrangement for standard theater projectors, using a 
*/4 horsepower 1800-rpm synchronous motor. 

Design of shutters and light sources requires an accurate method of 
analyzing the projector light-output pulse. A phototube light-pulse 
checker was devised for this purpose. Some actual results are shown 
in Fig. 7. "A" represents the sharp opening and closing edges with 
long-duration flat top, indicating a long period of constant-intensity 
illumination. "B" shows a light pulse from a prewar television pro- 
jector using a front shutter with an opening equal to the diameter of 
the light beam leaving the lens. The opening and closing require a 
relatively long time, while the maximum illumination persists for only 
a small time interval. 

Trace "C" shows the light pulse which is expected when the new 
pulsed-light mercury lamp is used. The opening and closing edges 
are almost infinitely steep and 
the top is flat, which gives an 
ideal system of operation. The 
sharp rise-and-fall edges provide 
an additional margin of safety 
within the television blanking 

By using a two-trace oscillo- 
scope it is possible to observe 
simultaneously the light pulse 
and the kinescope blanking pulse. 

With this technique the pulse 

FIG. 7. Light-pulse comparison, 
phasing, overlap, and the lock-in 

characteristic between the television synchronizing generator and 
projector synchronizing generator and projector synchronous motor 
can be studied in complete detail. 

The electrical details of the light-pulse checker are shown on the 
drawing of Fig. 8. The first tube is a 927 photocell, the second, a 
6J5 amplifier. A 6X5-GT rectifier tube furnishes a convenient d-c 
supply voltage. The light-pulse checker is placed at the focal plane 
of the Iconoscope camera tube and the amplifier output is connected 
to the vertical amplifier input circuit of a cathode-ray oscilloscope. 
The pulse duration can then be measured by using a synchronous 
60-cycle sine- wave sweep for horizontal oscilloscope deflection. With 
the pulse phased to be in the middle of the sweep, the width of the 
pulse, divided by TT times the horizontal sweep amplitude and 





Vol 48, No. 2 

multiplied by 100, will give the percentage time duration. The 
pulse checker can also be used to study any recurrent light pulse 
cut-off characteristics of standard theater projector shutters. 

A fundamental requirement of a projector is its ability to syn- 
chronize accurately with the television system. Synchronization is 
accomplished by virtue of the fact that both the television syn- 
chronizing generator and the special synchronous motor on the pro- 
jector have a common source of power supply. The special motor 
has several requirements; first, of course, it must lock in with the 
power line, and second, since a standard synchronous motor has two 

FIG. 8. Schematic light-pulse checker. 

lock-in positions, we must select the proper one. The projector can 
be incorrectly phased in such a manner as to be projecting a picture 
on the Iconoscope during scanning time; that is a lock-in 180 deg out 
of correct phase. To eliminate this possibility of error, the motor is 
built with a wound rotor having polarized field-coils so that it will 
automatically lock in with only one phase relationship. The motor 
used must be designed for small torque angle change with changes 
in load so as to avoid any tendency to hunt, and to maintain accuracy 
of lock-in for any changes in load due to film loading, or changes in 
adjustment of the projector during operation. 





Vol 48, No. 2 

Television Sound. Film-sound for a television system will place a 
challenge on the moving picture industry to maintain standards of 
excellence, since television uses frequency-modulation sound 
transmission and the public is being educated to appreciate in- 
creasingly improved standards. Sound-track reproduction from 

35-mm motion picture film has 
a fidelity comparable with that 
of the best vinyl recording 
transcriptions. Such quality ap- 
proaches the requirements for 
television sound broadcasting. 
The 16-mm film projector equip- 
ment can produce good sound 
quality, useful to about 6000 
cycles, but wide variations in 
16-mm sound recording and 
processing technique make de- 
sirable a 4500-cycle cut-off char- 
acteristic. Film-sound standards 
must be set high enough so that 
the listener will make favorable 
comparisons with existing radio 
"standards of sound performance. 
Functional Diagram 16-Mm 
Projector. The 16-mm pro- 
jector is shown in Fig. 9 func- 
tionally indicating the film path 
through the mechanism and 
over the sound drum to the 
lower take-up. The intermit- 

FIG. 10. 

RCA 16-mm television film 

tent is the claw type previously 
shown, with the shutter located 
immediately behind it. 

Television Projector 16-Mm. The RCA 16-mm television film 
projector, type TP16A, shown in Fig. 10, is a completely self-con- 
tained unit. The projector is mounted on a cabinet-type pedestal 
which contains the control equipment and the motor-field supply. 

The mechanism is that of the basic RCA PG201 projector, modi- 
fied for television systems using a storage -type pickup tube. A S 1 /^- 
inch//2 lens is used for projection of the image. The illumination is 

Feb. 1947 



furnished by a 1000-watt air-blast-cooled incandescent lamp. A 
special synchronous motor drives the timing shutter at 3600 rpm to 
give a pulse of six per cent duration. 

Fig. 11 shows the film side of the projector with covers removed 
from the machine and the pedestal. For normal operation the two 
circuitbreakers are closed, which 
completes the circuit to the 
motor-field supply, the audio 
amplifier, and the control cir- 
cuits. The stand-by switch is 
then closed, placing the projec- 
tion lamp on warm-up voltage, 
supplied through dropping re- 
sistors. The projector can now 
be placed in operation by closing 
the run switch, energizing the 
motor, and placing the lamp on 
full brilliance. An elapsed-time 
indicator is provided to record 
projection lamp hours. 

For installation it is necessary 
only to connect the equipment 
to a source of 220 v, 60-cycle, 
three-phase power for the motor, 
and 115 v, 60-cycle single phase 
for the projection lamp and 
auxiliaries. Control circuits with 
provision for remote operation 
are connected to the usual 12-v, 
d-c supply voltage common to 

most instaUations. FlG - n - , ^7^ removed from RCA 

television projector. 
Fig. 12 shows details of the 

shutter and drive gear. The small motor beneath the main drive 
motor operates a blower which ventilates the lamp house. The 
RCA rotary stabilizer used for the sound take-off drum is shown 
in the foreground. A ladder chain-drive powers the lower reel take- 
up. The amplifier assembly is a completely self-contained unit shock- 
mounted in the base casting. It consists [of a three-stage audio 
amplifier, designed to feed sound at a 4-db level to a 250-ohm line, 
an oscillator-type exciter-lamp supply, and the power-supply rectifier. 



Vol 48, No. 2 

FIG. 12. View of television projector 

jector, type TP35A (Fig. 13). 
This projector represents the 
latest advance in the art of 
motion picture projection for 
television. The basic machine is 

The base casting rests on level- 
ing screws to provide proper pro- 
jector alignment. 

Composite photographs have 
been prepared to show the new 
RCA 35-mm television film pro- 

FIG. 14. 

Film path of 35-mm tele- 
vision projector. 

FIG. 13. RCA 35-mm television 
film projector with Brenkert picture- 
head with GE Syncrolite. 

the well-known Brenkert BX 80, 
noted for its rugged design, 
automatic lubrication, and out- 
standing performance. The latest 
RCA high-fidelity soundhead 

Feb. 1947 



powered with a special synchronous motor is used as a companion 
unit. This combination is mounted on a deluxe Brenkert pedestal 
for rock-steady projection. The lamp house contains the pulse-light 5 
unit, complete, with all power supplies and auxiliaries. 

The operating side of the projector is shown in Fig. 14 to illustrate 
the clean and rugged design of the equipment. All bearings are 
automatically lubricated on the gear side of the Brenkert projec- 
tor, thus keeping oil away from the film side. 

Wide-mesh helical gears (Fig. 15) running in a continuous flow 
of oil provide a long-life, trouble- 
free mechanism. Oil is pumped 
from the reservoir in the base of 
the main frame to the rotary 
lubricator which throws the oil 
to all bearings and gears. The 
shutter governor is shown at the 
top, the framing adjustment 
through the link appears at 
the left, and the intermittent 
mechanism with its cam flywheel 
is shown at the lower right. A 
gear-case cover completes the 
assembly of the Brenkert pic- 
ture-head and provides an oil- 
tight gear case for the mechanism. 

The design efforts of many 
people are gratefully acknowl- 
edged. W. R. Isom of Advance FlG - 
Development devised the ellip- 
tical gearing and built the first 16-mm projector model. The RCA 
16-mm group under Sidney Read, Jr., engineered the 16-mm projec- 
tor, and Karl Brenkert, of Brenkert Light Projection Company, 
designed the 35-mm picture-head. The entire project was co-or- 
dinated by M. A. Trainer, of the Television Terminal Equipment 
Group, RCA Victor Division, at Camden, New Jersey. 


1 Reg. U. S. Pat. Office. 

2 ENGSTROM, E. W.: "A Study of Television Image Characteristics," Pt. I, 
Proc. I.R.E., 21, 12 (Dec. 1933), p. 1631; Pt. II, Proc. I.R.E., 23, 4 (Apr. 1935), 
p. 295. 

15. View of 35-mm television 
projector mechanism. 

110 R. V. LITTLE, JR. 

8 KELL, R. D., BEDFORD, A. V., AND TRAINER, M. A.: "Scanning Sequence 
and Repetition Rate of Television Images," Proc. I.R.E., 24, 4 (Apr. 1936), p. 559. 

4 KELLOGG, E. W.: "The Calculation of Accelerations in Cam-Operated Pull- 
Down Mechanisms", /. Soc. Mot. Pict. Eng., 45, 2 (Aug. 1945), p. 143. 

5 Supplied by General Electric Co., Syracuse, N. Y. 



Summary. The increased use of color in motion pictures has brought about a 
revival of interest in two-color bipack processes. With proper handling, allowing 
sufficient production time, and good co-ordination between camera, make-up f art, and 
wardrobe departments, the results with a two-color process are very adequate. 

The entire production program of the Hal Roach Studios is in a two-color process. 
The technical departments have had the advantage of planning for the limitations of a 
two-color process. This has enabled the studio to obtain the ultimate possible from 
such a process. This paper describes briefly some of the problems overcome and 
techniques developed. 

The increased use of color in motion picture production and the 
inability of the producers to secure sufficient three-color footage for 
release prints has brought a revival of interest in two-color bipack 
processes. With proper handling, allowing sufficient production time 
and good co-ordination among all departments, such as camera, 
make-up, art, wardrobe, property, etc., the results with a two-color 
process are very satisfactory. 

Since a two-color process can only record a limited range of colors 
successfully, this co-ordination between the various departments is 
absolutely essential. 

The Hal Roach Studio, upon reopening after the war, is producing 
all of its pictures in color. With the entire product of the studio in 
color, the technical departments have had the advantage of planning 
for the limitations of a two-color process. This has enabled the 
studio to obtain the ultimate possible from such a process. 

While a good deal of the following is common knowledge, we be- 
lieve no literature is available which has attempted to give practical 
assistance to the worker attempting two-color photography for the 
first time. 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
* * Hal Roach Studios, Culver City, Calif. 

112 J. W. BOYLE AND B. BERG Vol 48, No. 2 

With a few changes, any standard 35-mm cine camera can be 
utilized to photograph bipack film. These are the changes we have 
found necessary to convert the NC Type Mitchell for bipack: (1) 
Move lenses toward film (emulsion) plane a distance of 0.0045 in., 
then use normal calibrations for focus. Cameras with standard 
instead of "slip-ring" lens mounts would have to be either eye focused 
or recalibrated; (2) Adjusting lenses will necessitate "shimming" the 
ground glass back 0.0045 in.; (3) Remove "stripper" shoe at back of 
main sprocket and replace with "cutaway" shoe; (4) Lock off clutch; 
(5) Substitute either a four-roller pressure plate, or a solid pressure 
plate, for the usual two-roller pressure plate. In the four-roller plate 
the top roller is straight while the other three rollers are crowned 
0.003 in. The four-roller pressure plate is patented by the Cinecolor 
Corporation and license for use must be obtained from them. The 
solid-type plate is crowned 0.003 in. and is of polished chrome. 
Pressure can be obtained with a solid screw or by the use of a spring 
twice the tension of the normal spring. In practice we have used 
the solid screw for the four-roller plate, being careful to avoid "run- 

The proper adjustment of the pressure plate is very important; 
insufficient clearance with consequent "punching" will cause per- 
foration damage and out-of -register images, while too much clearance 
will destroy contact of the rear negative resulting in "breathing" and 
out-of -focus pictures. 

Too much stress cannot be placed upon adequate camera main- 
tenance . One of the most common faults in the use of bipack has been 
out-of -register prints owing to faulty camera operation. Nothing is 
more destructive of quality than an image that is degraded in sharp- 
ness and color because of lack of register. 

In the event the print is out of register and the negative shows no 
perforation damage, it would be wise to have the laboratory check the 
printing machine before assuming that the camera is at fault. Be- 
sides being mechanically perfect the printer, to obtain good register, 
should use the same perforation for registering the two negatives to 
the Duplitized positive as is used by the camera for register. Other- 
wise perforation idiosyncrasies may cause out-of -register prints despite 
good camera operation. 

As an aid in properly maintaining the cameras we photograph a 
test chart at the end of each day's work. The chart used at Hal 
Roach Studio is modified from one originally designed by the camera 


department of Republic Studios. An examination of the two nega- 
tives obtained is an excellent check on the camera's performance. 
Any lack of sharpness in the back negative, above that normally 
caused by the diffusion of the light passing through the front film, 
is easily noted. Another camera may be substituted and the camera 
sent to the shop for checking. Before the camera is used again an- 
other photographic check is made and the negative examined. 

We have obtained our best results with coated lenses. It is recom- 
mended that the wide-angle lenses should be carefully tested for 
covering power before being used. We have had satisfactory results 
with 24-, 28-, 30-, 35- and 40-mm lenses, but such wide-angle lenses 
should be used with discretion. The present 400-ft capacity magazines 
used for two-color bipack are wasteful of film and the constant re- 
loading necessitated by the short lengths uses up valuable production 
time. The Roach Studios are engaged in the design and construction 
of a 1000-ft magazine. 

The orthochromatic film in the bipack combination comes in two 
types : an exterior for daylight illumination, and an interior for tung- 
sten lighting. Because of the difficulties of obtaining a sufficiently 
high level of illumination with tungsten lights and variations in color 
temperature owing to aging of incandescent lamps, only the ex- 
terior type of bipack is used at the Roach Studios. This necessitates 
the use of high-intensity carbon arc lights and Macbeth filtered in- 
candescent units. 

Lighting practice for bipack is similar to that for any color process 
and will only be summarized briefly. Backlight is kept to a mini- 
mum; only the necessary amount used to give detail in hair and 
separate the planes of color. An undue amount gives an unpleasant 
bluish tinge. In exteriors, backlight makes grass and foliage appear 
brown and should always be avoided except when special effects are 
desired. For street scenes and exteriors where there are no deep 
shadows, overcast days have given us our best results (since we always 
use high'-intensity arcs, and booster lights) for foregrounds and 
faces. The use of an Aesculin-type filter to cut the ultraviolet helps 
in rendition of face values, skin textures, and colors. In general the 
set should be fully lighted, avoiding deep shadows. With coated 
lenses at f/2.8, a keylight of 500 ft-c is used, filled to an over-all of 
650 ft-c. 

For night effects, and somewhat deeper shadows, less fill and more 
crosslight is used. The negative should be fully exposed, the proper 

114 J. W. BOYLE AND B. BERG Vol 48, No. 2 

effect being obtained by printing down. Night effects are accen- 
tuated by the use of "practicals" and brightly lit windows. In prac- 
tice about 20 per cent of the lights used are incandescent lamps with 
Macbeth whitelite filters. Occasionally ordinary incandescent spots 
are used without Macbeth filters to bring out or emphasize reds and 
orange, or in the photographing of colored characters. Because of 
the volume of light necessary, large units are used as far away from 
subjects as set construction will permit. A Y-l filter is used on all 
high-intensity spots, to cut the excess of blue, while the Mole-Richard- 
son broadsides are used without filters. The side arcs are 5500 K. 
The high-intensity arcs with 170- Y-l Brigham filters are 5900 K. 

No specific rules can be given for make-up since the problem changes 
with the actors and actresses. In general, in a two-color process the 
make-up should be on the light side to avoid a red-orange or sallow 
appearance. Lip rouge should be an orange-red, blue-reds photo- 
graphing much too dark. We have found grease to be more satis- 
factory than "pancake" and no make-up is used above No. 25. 

Because of the light make-ups, blended modeling is used to prevent 
masking appearance and to break color up into planes. For men, 
a beard cover must be used; otherwise the beard comes through as a 
blue shadow. No make-up is used on children. The make-up must 
be carefully balanced between characters to avoid extremes. Flesh 
tones are best rendered when the print is on the light side. Dark 
prints cause tones to take on an orange cast rather than the more 
desirable pink appearance. Make-ups made for existing three-color 
processes have not been found satisfactory. Standard black-and- 
white technique in lighter shades has been found more suitable. 

The successful use of two-color bipack requires the most careful 
selection of colors in both sets and wardrobe. Certain difficult colors 
should be avoided and the most painstaking attention paid to the re- 
lationships of colors used. The use of pastel tones of colors produce 
the best results. Excessive use of brilliant colors is to be avoided 
except in small areas for emphasis only. Colors darker than the 
middle range of the scale should not be used except where special 
effects are desired. This is because all dark colors tend to reproduce 
with a certain sameness, giving a monotone effect. The use of black 
and white is good in this regard, to give added range. Contrasting 
colors used together are excellent for heightening color effectiveness. 
Blue appears bluer by virtue of being adjacent to a yellow. In men's 
wardrobes too many grays should be avoided since they tend to 


reproduce alike, leaning to the blue-green. For white shirts, towels, 
bedding, etc., we use a buff color, rather than the usual gray, since the 
buff reproduces a better white. Browns reproduce fairly accurately, 
therefore graduations can be better judged. In the selection of ward- 
robes it is better to make actual photographic tests. 

It should be remembered that only the faces are the really fully 
lighted areas so that clothes are somewhat underexposed. This tends 
further to degrade dark colors. In general, grays reproduce with a 
greenish cast, yellow goes orange-brown, reds on the magenta side, 
tend towards brown, orange-reds reproduce the brightest. Fluorescent 
cloth used for stage productions reproduces with unusual brightness 
and can be used effectively where a very brilliant color is desired. 

In all instances it is best to make photographic tests of both sets 
and war'drobes prior to actual production. It is essential that the art 
director, the wardrobe designer and the cinematographer work 
closely together to achieve a harmonious result. 

Adequate liaison between the color laboratory and the studio is 
most important, both in keeping the cinematographer informed about 
his negative and in assisting the laboratory in achieving the effect 
the cameraman is striving for. * 

Process shots, matte shots, wipes, dissolves, speed work, etc., 
can all be done in t wo -color bipack; in fact, anything which is possible 
in regular black-and-white photography is feasible in two-color bi- 



Summary. As a service organization for a large number of 16-mm producers 
in this country, we are constantly impressed with the obvious lack of adequate equip- 
ment for making good 16-mm sound. This paper is, in fact, a plea for general im- 
provement in the engineering management and design of sound channels for 16-mm 
recording. This paper, recognizing the lack of availability of specialized 16-mm 
equipment, describes the practicability of adapting standard broadcast and disk re- 
cording equipment to 16-mm work. This may at first seem obvious, but many 16- 
mm producers still think that a 16-mm recorder requires a "16-mm amplifier." An 
attempt is made to convey to the producer the fact that while we cannot buy new 16- 
mm recorders and film phonographs, we can surround our present recording units 
with finely engineered sound channels for recording and reproducing that will repre- 
sent fine quality for years to come. 

During the past two years there has 1 been a definite increase in the 
number of industrial motion pictures made in this country. Some 
were made by new producers, some by old established firms. The 
Calvin Company, as a service organization, has had the opportunity 
to hear and appraise much of this work. 

Many sound tracks go through our plant every month. Some are 
processed, some are printed. Quite often the job is an old 35-mm 
track for rerecording to make it usable, or an improperly recorded 
16-mm track, or a disk recording to be transferred to film. Levels 
must be smoothed out, volume raised to commercial standards, and 
tracks re-equalized to make them intelligible. Excellent tracks are 
the exception. We do hear them, they are being made, but not too 
often do we hear a sound track that could not be improved by the 
use of better sound channels. 

An engineer, walking into this business for the first time, notices 
the equipment first, or rather the lack of it. This is the only branch 
of the electronic industry I know of that does not have competitive 
equipment and lots of it. It would have a wholesome effect on the 
16-mm industry if several manufacturers were to enter the electronic 

* Presented Oct. 23, 1946, at the SMPE Convention in Hollywood. 
* * The Calvin Company, Kansas City, Mo. 


side of it and make new recorders and film-phonographs available 
but that is for the future. 

Your present problems are not theoretical, they are practical. 
We want to make better sound quality today. I cannot tell you how 
to get a new recorder or a new film phonograph, but I can make sug- 
gestions that might make it possible for you to make better quality 
with your present recorders. While I, personally, believe that many 
of the 16-mm and 35-mm light modulators used in this country 
are considerably less than perfect, it is still true that the average 
producer is not turning out sound tracks as good as his recorder is 
capable of making. 

So let us design sound channels around our recorders that will 
represent fine quality for years to come, and will feed into the re- 
corder quality at least its equal, and generally better. We can do 
something about the quality we deliver to our recorders, and we can 
do something about the quality after it leaves our reproducers. It is 
the purpose of this paper to discuss these problems, and to describe a 
typical sound recording channel suitable for a permanent film and a 
disk installation, and the choice and use of the components that make 
it up. 

Whether you record on paper tape, magnetic wire, 16- or 35-mm 
film, or rotating disks, your basic problem is the same. It is adequate 
power with good wave form. You will never make better quality 
than the weakest point in your sound system. So I think a wise thing 
to do is to let the weakest point be the recorder or the film itself. I 
think that is a practical answer to a present problem. Also, a good 
sound channel today will be a good sound channel five years from to- 

. Now, how would you build a sound channel for a 16-mm recorder? 
What are the basic requirements for 16-mm sound? Many producers 
still think that a 16-mm recorder has to be fed with a 16-mm ampli- 
fier. That is not true. The signal feed into a 16-mm recorder is 
fundamentally no different than the signal fed into a radio trans- 
mitter, or into a public address system, or into a disk recording head. 
The only difference lies in the shape of the curve, which is an equalizer 
problem, and the amount of power required. Basic quality is quality, 
regardless of what you are going to do with it. 

Now where do we get good quality ? It comes from good equipment 
properly used. Fortunately there is excellent sound equipment 
available today. The one fundamental and essential of all quality 

118 A. JACOBS Vol 48, No. 2 

' is good wave form. Maintaining good wave form throughout a re- 
cording channel is an engineering problem of high order. You will do 
it only with finely engineered equipment. You will not get good 
wave form in cheap equipment, and you will not get it in equipment 
improperly used. 

Now, for our typical sound channel. Basically, most recording 
sound circuits are the same. For convenience we shall divide them 
into five parts. 

(I) The sound source may be one or more microphones previously recorded 
film, reproduced by film phonographs or previously recorded disks, reproduced by 
disk reproducers. All of these sound sources require immediate amplification. 
This is called preamplification. 

(2} After preamplification a common practice is to equalize.' Possibly the most 
complex problem in all 16-mm work is equalization because it is by equalization 
that we are able to utilize the limited frequency response of 16 mm, film so as 
to make it practical. 

(5) After equalization comes mixing. Mixing permits the artful blending of 
our various sources of sound, so as to produce in one track the composite whole 
which is our objective. 

(4) Following mixing is a logical point in our circuit arrangement to use com- 
pressors or limiters. They are practically indispensable in achieving high volume 
levels. This is specifically true in voice recording. 

(5) After compressors or limiters comes power amplification. The power 
amplifier, in turn, drives the light modulator or any other recording device that 
may be used. 

Thus we have sound source, preamplification, equalization, mix- 
inglimiting 6r compression and, finally, power amplifiers. 

Now, let us discuss these five parts of our sound circuit separately. 
First, sound source: The first thought of sound source is a micro- 
phone. Of the large number and variety of microphones made in 
America, only a few are really suitable for film work. Since the pos- 
sible frequency response on 16-mm film is restricted, and many 16- 
mm modulators possess poor dynamic stability, the shape of the curve 
fed the modulator becomes very significant. It is important, there- 
fore, that we use a microphone with a smooth frequency response 
permitting us to shape these curves later with our equalizer networks. 

While it is true that, many times, a diaphragm-type microphone 
with a definite resonant characteristic makes what seems to be a 
better track, generally it is more desirable to use a microphone with 
an essentially smooth response, and shape the curve later with our 
equalizers to suit the characteristics of the modulator and the film. 
This is particularly true inasmuch as the dynamic instability of the 


modulator is often aggravated by the resonant frequency of many 
microphones. This means one should not buy cheap microphones. 
It does not mean, however, that all expensive microphones have 
smooth response characteristics. 

Another sound source is a disk recording. We do considerable 
rerecording from disk to film for clients, who for various reasons do 
not wish to record directly onto film. Disk recording is a flexible, 
practical way to record if you make good records. What is true re- 
garding sound channels for film recording will also be true for disk 
recording. A smooth frequency response, carefully equalized to suit 
the reproducer characteristic to be used, can result in a disk recording 
very practical for rerecording to film. The days of poor disk repro- 
ducer and the wobbly turntable of erratic speed are over. There is no 
necessity for using inferior disk recording or reproducing equipment. 

Our last sound source to be mentioned is the film phonograph. 
You cannot run down to the corner and buy a new film phonograph. 
All you can do is pick the signal up where it leaves the photocell and 
feed it into the best preamplifiers you can buy. 

Now, all these sound sources mentioned above require amplifica- 
tion by preamplifier before the signals we get from them can con- 
veniently be handled. Preamplifiers are very important. They es- 
tablish our original signal-to-noise ratio which we cannot alter after 
the signal leaves the preamplifiers. A preamplifier should bring the 
level of our sound source up to where it can be handled conveniently. 
Generally a gain of about 40 db is satisfactory. The noise level should 
be about minus 90 under one milliwatt, weighted. Synchronization 
work, where long pickup distances are often necessary, requires con- 
siderable amplification, making it very necessary that our preampli- 
fier be very quiet. It should have a flat frequency response from 20 
or 30 cycles to 15,000. Its input and output impedances should be 
standard. Regardless of any inherent superiority of one impedance 
over another, impedances have become fairly standardized the last 
five years, and it is very annoying to have equipment that requires 
external matching transformers. There is no reason to buy pre- 
amplifiers that will not approximate these specifications. Distortion 
characteristics will be mentioned when we discuss power amplifiers. 

After we have amplified our weak signals from our sound sources 
they are ready for equalization. As previously stated, possibly the 
most complex single problem in producing 16-mm quality, assuming 
we have good audio channels, is equalization. A narrator's voice 

120 A. JACOBS Vol 48, No. 2 

seldom requires the same kind of equalization as an orchestral back- 
ground or an organ background, so it is very desirable to have separate 
equalization for every sound source. This means equalization has to 
be done before we mix these signals. The level coming out of a two- 
stage preamplifier is generally around minus 30. This is a convenient 
equalization level. Levels up to around zero may be used, but some 
equalizers lose some of their equalizing ability if too high levels are 
fed into them. 

The demand by the broadcasting and disk recording industry a few 
years ago was responsible for the evolution of our Standard Broad- 
cast Equalizer. They are suitable for much of our film work. Most 
commercially available equalizers have four selector points for the 
high-frequency end, and three points for the low-frequency end. 
The high end is generally topped at 4000, 6000, 8000, and 10,000 
cycles, and the low end at 100, 50, and 25 cycles. In any ordinary 16- 
mm work the 4000 cycle point is generally used. The 8- and 10-kc posi- 
tions are superfluous. However, if other than 16-mm recording is to 
be done thay are essential. Probably 85 per cent of the recording on 
16-mm film should be equalized to around 4000 cycles. 

The low end is relatively unimportant as very little equalization 
is ever needed. If needed, some point around 100 or 150 cycles is 
suitable. A 50-cycle tap and a 25-cycle tap are practically useless. 
That is also true for disk recording. We do need low-frequency 
attenuators, however, and their use is essential for the shaping of our 
curve that is to be fed into the modulator. So, for the average 
equalizer requirements for 16-mm, the ordinary commercial equal- 
izers will be adequate. The low-frequency attenuators available are 
also adequate for most work. These units, like the low-frequency 
equalizers, are generally tapped at around 150, 100, and 50 cycles. 

The units just described are very suitable for much 16-mm work 
and for many producers would be entirely satisfactory. However, 
at our plant the requirements are a little more severe. Many re- 
recording jobs are sent into our plant that require radical equaliza- 
tion to make the sound tracks usable. Sometimes the intelligibility 
is so poor that we have to equalize at a point as low as 1500 cycles 
to make the track understandable. The demand for this type of work 
made it necessary to build suitable equalizers that were flexible 
enough to meet any of these extreme conditions, and at the same time 
satisfy the need for our ordinary requirements. Our latest equalizers 
have taps every 500 cycles from 1000 cycles to 7000 cycles. On the 


low end they are tapped at 500, 300, 200, and 100 cycles. The shape 
of the curve, on the low end especially, differs somewhat from that 
generally used in commercial equalizers. It cuts off more sharply; 
that is, after the curve breaks, it falls faster. We find this more 
practical in creating the desired balance between low- and high- 
frequency energy that is so necessary in work where the frequency 
range is restricted. 

' The use of equalization, like mixing, is almost an art. The recog- 
nized fact of the frequency response limitations of 16-mm work makes 
it absolutely necessary that we utilize the frequency width available 
in the most advantageous way. Most engineers know that the shape 
of the curve is, in many instances, more important than the width 
of the frequency response. Quality on 16-mm film demonstrates 
this very clearly. It requires the highest skill and the finest equip- 
ment to put a signal from 80 cycles to 4000 cycles on a finished print 
of a 16-mm sound track and on color film it is even more difficult. 
These limitations are primarily dimensional. When it is realized 
that at 36 ft per min, which is 7.2 in. per sec, the image size of a 2- 
kc tone is approximately the same as a 5-kc tone on 35 mm. In other 
words, it is harder to record 4 kc at 7.2 in. per sec than 10,000 cycles 
at 18 in. per sec. This creates an acute problem, not only of the fre- 
quency response attainable, but also of wave form, thus justifying 
our previous care as to the wave form characteristic of our sound 

We utilize the restricted frequency response of 16-mm film by shap- 
ing the curves so as to overcome or partially neutralize the inherent 
limitations of the film and the reproducing equipment. Many studies 
in recent years show clearly that there is a necessary balance between 
high-frequency cutoff and low-frequency cutoff to produce pleasing 
quality. This is very significant in 16-mm work because we are 
actually obliged to create what quality we can within a frequency 
range of between about 80 cycles and 4500. If there is any secret to 
equalization, it is to have equipment flexible enough to create curves 
to suit any requirement of our sound source, however severe. 

After we have equalized our various sound sources, they are ready 
to be mixed into a single composite signal. A mixing panel is a rela- 
tively simple affair, but much thought should be given to its flexibility 
and convenience of operation. A good mixer should be designed by 
an engineer and most manufacturers of mixing equipment will help 
you with mixer design. 

122 A. JACOBS Vol 48, No. 2 

After our signals are equalized and mixed, it is practical to feed them 
into a limiter or compressor amplifier. High average volume levels 
are hard to maintain without some method of controlling sudden 
peaks of energy, and sudden peaks of energy are very common in 16- 
mm when, by equalization, you emphasize the energy in the sibilants 
of a narrator's voice. From these limiting or compression-type 
amplifiers, we can drive our power amplifiers. 

Power amplifiers are just what their name implies. They take tKe 
mixed and equalized signal and increase its power until it is sufficient 
for the work to be done. The requirements of a good power amplifier 
are as severe as for any of our equipment. The frequency response 
should be as wide as our preamplifiers ; the noise level should be very 
low. It should not be possible to hear a good power amplifier when it 
is coupled directly to a good speaker and is running wide open. That 
means a noise level at least 50 db below 6 milliwatts. In a sound 
channel, such as I am describing, a gain of from 60 to 75 db should be 
available in the power amplifier. 

In the light of our new knowledge gained during the past five or six 
years, new standards of excellence have been set up for amplifiers. 
This means preamplifiers, line amplifiers, compressors, and power 
amplifiers. Many engineers remember when we could do a frequency 
run on an amplifier at some indifferent volume level, and if it was 
reasonably flat it was considered a good unit. Then we began to 
appraise wave form that is, steady-state wave form, such as a con- 
stant tone from an oscillator. Everybody was happy when, in con- 
junction with our reasonably flat frequency run, we also took a read- 
ing on our harmonic distortion and found it was only a few per cent. 
But many engineers remember that even when our frequency response 
looked good, and our steady-state wave form distortion crept down 
to around 2 or 3 per cent, quite often our quality seemed to be imper- 

Gradually it came to be recognized that other characteristics of our 
amplifiers and speakers and microphones were involved that meas- 
uring these components with steady-state signals was not enough. 
Finally it has become recognized that wave form is an extremely 
complex thing and is the basis of most of our quality. 

We are just entering an era in amplifier design where the design 
engineer is obliged to recognize there is something more than just a 
good frequency response necessary something more than steady- 
state distortion of one or two per cent. This "something more" is the 


ability of the amplifier to take a complex wave form and amplify it 
without adding to or subtracting from its complexity. The inability 
of an amplifier to amplify several frequencies at the same time pro- 
duces a form of distortion called "intermodulation." 

Intermodulation distortion appears to be one clue to that intangible 
something that sound engineers have heard for years, but were never 
quite able to identify. Equipment is appearing on the market now 
that permits us to begin measuring this sickness in our sound chan- 
nels. Amplifiers are not the only offenders in possessing intermodula- 
tion distortion. Cutting heads for disk recording are a common 
example. Record reproducers may have it, light modulators have it, 
and, of course, loudspeakers are very much subject to it. So we have 
added another specification to our amplifiers throughout our whole 
recording channel. 

Last, but not least, I want to emphasize the power handling capac- 
ity of your amplifiers and the power necessary to drive various pieces 
of equipment. When you have a light modulator that requires, say, 
+ 20 db to drive it that is, the manufacturer says it takes only 
+20 to drive it how much power do you think an amplifier should 
be able to deliver? Plus 20 above a 6-milliwatt reference level is 
0.6 of a watt. It is impossible to drive it with 0.6 of a watt, or twice 
0.6 of a watt, or even 3 times 0.6 of a watt, and do a good job. The 
instantaneous values of power involved in following a complex wave 
form may swing many times above the basic power rating of the 

This is also true of disk recording head ratings. It does not hurt 
to have too much power if it is good and clean. So, be sure the am- 
plifiers have a large excess of power above what the work requires. 
Good clean power available in 12 or 15 w is not too much to ask for 
in most recording work. A sound channel that will deliver this much 
power makes it convenient to switch to disk recorders, also. 

Now, the typical recording channel I have just outlined can de- 
liver an excellent signal to any recorder. It can shape this signal so 
as to take full advantage of the recording medium to be used. It will 
represent good quality for years to come. As film recorders are made 
available or new ones developed it will still be suitable. The use of 
standard components makes replacement easy, although it will be 
many years before a 30- to 15,000-cycle signal of adequate power with 
excellent wave form characteristics will not be considered fine quality. 

So, we have available excellent sound channels, we have recorders, 

124 A. JACOBS Vol 48, No. 2] 

and I am sure better ones are on the way. All we lack now is a very 
important factor, and that is personnel. The 16-mm sound business 
needs operating engineers. We can get them from two fields. One is 
the 35-mm business and the other is the broadcast business. 

The broadcast field offers the greatest possibilities. This country is 
full of good broadcast engineers, many with disk recording experience, 
who need only a short breaking-in period to become good 16-mm men. 
For example, any good broadcast engineer would consider the typical 
sound channel I have described as an ordinary straight-forward 
channel with the exception, perhaps, of the extra attention we pay 
to the equalizers. Quality is an old subject to him. The use of 
microphones and amplifiers and mixers is his every-day problem. 
However, a word of warning: Know what you are looking for in an 
engineer before you choose one. 

This paper is really nothing more than a plea to the manufacturers 
to deliver us better film phonographs and recorders, and a plea to the 
producers to take advantage of the fact that they can have excellent 
sound channels immediately and can find personnel to operate them. 


MR. H. C. MOORE: How much improvement can be expected by equalization 
before mixing as compared to equalization after mixing? 

MR. JACOBS: Suppose a narrator is talking and you wish to put music and 
sound effects behind his voice. The same equalization used on his voice is 
generally unsuitable for music, quite often ruins music. The best equalization for 
music is generally bad for voice. Obviously, it is better to equalize these signals 
separately and then blend them in the mixer. 

MR. C. R. SKINNER: Could you give us an idea of any definite standard curve 
that you would have, for instance, for a voice recording, and a standard curve for 
a music recording which would be used in 16-mm work? For recording, it is 
necessary to have some sort of a curve to begin with. Have you set up a stand- 

MR. JACOBS: I do not have any proposal. I do not think 16-mm could bear 
such a standardization yet. The sound sources are too varied. Several pictures 
could be shown here and no two will sound alike. I am not particularly sold on 
standardizing 16-mm in that respect. However, it might be a good idea if there 

MR. SKINNER: That is the problem: It is a question of whether you are going 
to do it on the projector or recorders. In the old days in 35-mm they went 
around that same vicious circle until a standard was established. 

MR. JACOBS: I grew up in the disk recording business; and disk reproducers 
are not standardized yet, after 20 years. The new Western Electric has seven 
equalizer positions on the playback circuit, two on the vertical, and five on the 
lateral. Standardization is not possible until the manufacturers standardize the 


reproducer characteristics. How are you going to know when you make good 
quality? All you can do is choose a projector that is considered fairly standard 
and make pictures which sound good on it. Even then, some will sound bad on 
another make of projector. One has to try for a happy average. 

MR. C. R. KEITH: When you are playing a record that you have made on 
your equipment, on one of these projectors which you consider average in the area 
you are operating in, do you play that record on the medium position of the tone 
control, or elsewhere? 

MR. JACOBS: We arbitrarily have chosen the position on our volume control of 
about "11:30," and "12:00 o'clock" on our tone control for black-and-white, and 
"1 : 00 o'clock" for color track. We realize if it has plenty of volume at "11 : 30" 
it is a satisfactory track. If it sounds good, regarding balance at "12: 00" or 
"12: 30" on the tone control, it is satisfactory. 

MR. GEORGE TALLIAN: I am very much surprised you did not mention any- 
thing about flutter in 16-mm sound. It seems to me that flutter is the biggest 

MR. JACOBS: I was speaking only of the sound channels. Flutter is a me- 
chanical problem, and I could not cover that. Of course, I agree with you, there 
is a problem there. However, the new recorders probably will not have any 
appreciable amount of flutter. 


The year 1946, on July 24, marked 30 years of achievement in 
motion picture engineering and standardization for the Society of 
Motion Picture Engineers. From its first organization meeting the 
Society has had as its fundamental aim the standardization of motion 
picture film, equipment, and accessories from the standpoint of 
dimensional tolerances, data, processes, nomenclature, and the like 
which either directly or indirectly might be applicable to the produc- 
tion, distribution, and exhibition phases of the motion picture indus- 
try. The early organizers, many of whom are now well-known engi- 
neers and scientists in this industry, did at their first meetings 30 
years ago originate proposals to become standards of the SMPE, as 
the American Standards Association did not exist. These proposals 
and SMPE Standards were reviewed and redrafted many times before 
eventually becoming American Standards in the early 30's. 

These early organizers of the SMPE were fully cognizant of the 
importance and value of international standards in any industry. 
They appreciated that the universal acceptance of standards inter- 
nationally brought about understanding and friendship, encouraged 
freedom of design and application, expanded world markets for 
trade, and permitted interchange of products from one nation to 
another. The first decade of output was not great in quantity, but 
quality was being generated to produce well-planned proposals for 
standardization . 

In the second decade, the late 20's and early 30's, numerous pro- 
posals and SMPE Standards became American Standards of the 
American Motion Picture Industry. In the early 30's and from then 
on, the Society entered into and, in so far as possible until the be- 
ginning of World War II, continued co-operation with the British 
and Germans on internationalizing Motion Picture Standards. 

* Presented Nov. 21, 1946, before the Conference of Staff Executives of the 
Member-Bodies of the American Standards Association, New York. 
** President, Society of Motion Picture Engineers. 



The SMPE proposed in 1932 that 16-mm motion picture film be 
projected with the emulsion facing the lens, just the opposite of what 
was and is the standard practice with 35-mm motion picture film. 
In April 1933 the Germans copied the SMPE proposal and circulated 
their draft, but it was not until November 1933 that discovery was 
made that the German Proposal was the exact opposite of the SMPE 
or American Proposal." This discrepancy arose from a lack of familiar- 
ity with each others' languages. The SMPE, on invitation from the 
Germans and British, appointed a representative to attend confer- 
ences at which the differences were to be adjusted. These were held 
in June 1934 through April 1935 in Rome, Baden Baden, Stress, and 
Berlin. Then, in July 1935, George Freidl of the SMPE and J. W. 
McNair of the ASA left the United States for a final session on the 
subject at the International Congress of Scientific and Applied Photog- 
raphy in Paris, France. 

After much discussion, the SMPE Proposal was accepted. Not 
all proposals or American Standards have such misfortune in becoming 
internationalized. This case is sighted merely to show that the 
SMPE has followed its original aims and purposes. It should be 
mentioned that this one problem of settling an international standard 
did bring about better understanding and greater appreciation of the 
other fellow's problems. 

In the past decade an even more active program has arisen. 'Within 
the past few months the SMPE has forwarded 26 new and revised 
American Standards on Motion Pictures to the American Standards 
Association, requesting that they be submitted to the United Nations 
Standards Co-ordinating Committee for consideration as proposals 
for International Standards. The SMPE recommended also that 
the ASA propose to the UNSCC that the Secretariat for Motion 
Pictures on International Standards be located in the United States, 
as this country has been the leader in production and standardization 
of motion pictures. This has now been done with the formation of the 
International Organization for Standardization. 

An additional ten proposals for American Standards are now, in 
various stages, drawing rapidly toward completion, and it is our in- 
tent to recommend to the ASA that these also be submitted to the 
new international organization. The Research Council of the Acad- 
emy of Motion Picture Arts and Sciences and the SMPE are preparing 
mutually 35-mm and 16-mm picture and sound test reels, both for 
practical use by the projectionist in the theater and for scientific 

128 D. E. HYNDMAN 

measurement purposes by the equipment design engineer, which will 
be submitted as proposals for American Standards and recommended 
to the ISO. Numerous other projects for standardization are being 
considered by the Research Council and the SMPE. 

If we are to enjoy international harmony there must be unity of 
effort by all peoples of all nations toward appreciation of the ideas 
and ideals of each. No better road can be taken than the one down 
through science, engineering, research, producer, distributor, and 
consumer to reach International Standards. 




Summary. Among the devices for light control are color filters for separation 
selection, neutral filters for supplementary control of exposures, and polarizing filters. 
Polarizers may be used in photography for the control of reflections and for exposure 
and contrast control of certain surfaces. Among the many uses of polarizers which 
are of interest in photography is their application to photoelastic analysis. Another 
application is in the production of special effects in color and black-and-white photog- 
raphy. Of particular interest is the application of polarizers and polarizing photo- 
materials to three-dimensional photography. 

The paper discusses briefly the fundamental mathematics involved in the polarizing 
effect with particular reference to crossed polarizers. 

This paper is confined to photographic uses of polarizers. It does 
not attempt to explore their many nonphotographic uses. 

An Analysis of Light Polarization. Let us imagine we are look- 
ing head on at a beam of light and that we can conceive it in the 
form shown in the diagram (Fig. 1). This represents a complicated 
cluster of directions of vibrations such as we assume exists in ordinary 
unpolarized light. This diagram attempts to illustrate that light 
vibrations are in infinite directions at right angles to the path of the 
light. If by some means all the waves in a beam of light are made to 
vibrate in planes parallel to each other the light is said to be plane 

For simplicity in illustrating the effect of plane polarization we may 
use the kind of representations shown in Fig. 2. In A , the unpolarized 
light is shown entering polarizer 1 and emerging as horizontally polar- 
ized light, the polarizing axis of the polarizer being horizontal, and 
entering another polarizer 2, whose axis also is horizontal. With the 
polarizing axes of both parallel, the polarized light passes through the 
second polarizer without loss, except for absorption in its passage 

* Presented May 8, 1946, at the Technical Conference in New York. 
* * Loucks and Norling Studios, New York. 




Vol 48, No. 2 

through the second polarizer. In B, the polarization axis of the 
second is crossed at 90 deg with that of the first polarizer, and the 
light is extinguished. In C, the second polarizer is turned at a smaller 

angle than in B and the light is 
diminished in passing through. 

Now, let us investigate more 
fully what happens when a polar- 
izing filter is placed in the beam 
of light. The diagram of Fig. 3 
shows a broken horizontal line 
A, which represents the axis of. 
polarization of the polarizer. The 
polarizing filter transmits not 
only the vibrations which are 
originally parallel to the polariz- 
ing axis, but also the horizontal components of all the infinite 
number of other directions of vibrations. Consider the vibra- 
tion identified by the symbol A\ lying at angle a to the axis of the 

FIG. 1. 

Representation of a cluster 
of light vibrations. 

FIG. 2. Illustrating the effect of plane polarization. 

polarizer. A\ will have a horizontal component A x . And so with all 
the other inclined vibrations in accordance with their inclinations. 

Vibrations may be represented by triangle-of-forces diagrams. 
In the vector diagram shown in Fig. 4, line A\ represents the ampli- 
tude of a vibration and its direction. Its length is a measure of the 

Feb. 1947 



magnitude of the vibration . Let us suppose that the line A i stands for 
the amplitude of the light vibrations coming from the first light 
polarizer (in C, Fig. 2). Let the line A x represent the polarizing axis 


FIG. 3. Analysis of a single direction of vibration. 

of the second polarizer. The amplitude A\ gives a component along 
the direction A x equal to 

AI cos a 

where a is the angle between AI and A x . 

The energy of a vibration is 
proportional to the square of its 
amplitude. Thus 

I u = I cos 2 a 

where I u is the relative intensity 
of light transmitted by two polar- 
izers when the angle between 
their polarizing axes is a\ and I 


-A t cos % 

FIG. 4. Vector diagram of a vibration. 

is the relative intensity of the transmitted light when the angle 
a is zero. 

The curve shown in Fig. 5 is a graphical representation of the above 
formula, with I arbitrarily equal to unity. The curve and the formula 
are strictly true only for perfect polarizers. 

An ideal polarizer should have a transmission coefficient of 0.50 
but this is not attainable because of light losses at the front and back 



Vol 48, No. 2 

surfaces of the polarizer resulting in a reduction to a transmission 
coefficient of about 0.46. In addition, all polarizers absorb a certain 
amount. In the case of the best polarizers available for photography, 




FIG. 5 










) 10 20 30 40 50 60 70 80 9 

Relative transmission of light through supe 

posed polarizers. 

FIG. 6. Showing double refraction in calcite. 

the transmission coefficient is between 0.40 and 0.42. Polarizers for 
photography must be substantially neutral in color, have even ab- 
sorption, be free of flare and fluorescence. 

Natural Polarizers. Some natural crystals are polarizers. 
Among these is calcite, which has the peculiar property of splitting 

Feb. 1947 



the light so that two separated images are seen through the crystal. 
Fig. 6 shows the effect. 

In calcite the incident light ray is divided into two rays which are 
bent differently (Fig. 7) . Thus calcite differs from glass in that it has 

FIG. 7. Illustrating the double refraction in calcite. 

two indices of refraction. In passing through the calcite the two 
parts of the ray are perfectly polarized, and when they emerge they 
are polarized exactly at right angles to each other. In other words, 
the calcite resolves all vibrations of the incident light into two com- 
ponents at right angles to each other, and it then transmits them 
with different speeds. 

FIG. 8. Diagram of a Nicol prism. 

The double refraction of light by calcite was first observed by the 
Swedish physician Erasmus Bartholinus, in 1669. Huygens and 
Newton later studied the phenomenon in detail. 

Nearly all crystalline substances exhibit double refraction. To 
mention but a few, we find that quartz, sugar, mica, and ice show 
the effect. 



Vol 48, No. 2 

The two opposite faces of a calcite crystal are parallel to each other, 
and the two refracted rays emerge parallel to each other but dis- 
placed, as shown in Fig. 7. When the incident light enters, 
one ray, called the ordinary ray 0, passes through without bending 
and is polarized in one plane, while the other ray, called the 
extraordinary ray E, is polarized in a plane at right angles from the 
other and is bent away from the ordinary ray. The ray obeys 
the ordinary laws of refraction and for the ray the crystal acts 
like glass. In other words, the ray travels with the same velocity 
regardless of its direction through the crystal and its axis of polari- 
zation is always perpendicular to the optic axis. But the velocity of 
the E ray is different in different directions. 

FIG. 9. 

Illustrating a tourmaline crystal and the absorption 
of the O ray. 

It is possible to make prisms of calcite which eliminate one of the 
polarized rays. They are known as Nicol prisms, from the Scottish 
physicist Nicol, who made the first one in 1828. They have long 
been used in polarizing microscopes. Nicol prisms are limited to 
small size and are quite expensive. 

Fig. 8 shows a diagram of a Nicol prism. The prism is made by 
cutting a calcite crystal along a diagonal and cementing it back to- 
gether again with Canada balsam, which is used because it has a re- 
fractive index midway between that for the and E rays. Conse- 
quently, there is a critical angle of refraction for the ray but not 
for the E ray. The ray is totally reflected by the Canada balsam 
surface, while the E ray passes through and emerges parallel to the 
incident light. If two Nicols are lined up they form an optical system 
frequently used in microscopes for studying the optical properties of 
other crystals. The first Nicol produces plane-polarized light as do 


the polarizers 1 in Fig. 2. It is called the polarizer. The second Nicol, 
corresponding to polarizers 2 in Fig. 2, is used to test the light and is 
called the analyzer. 

Some crystals, such as tourmaline (Fig. 9), exhibit double refraction, 
in much the same way as in calcite but with the difference that the 
vibrations are entirely absorbed by the crystal while the E vibra- 
tions pass through. Thus, tourmaline has selective absorption and, 
in this respect, is like the Nicol prism, for it takes in ordinary light, 
disposes of the vibrations, and transmits plane-polarized light. 

The behavior of this crystal, and many other substances, is caused 
by the molecular structure. To draw an analogy, regularly spaced 
molecules are like the pickets in a fence. A stick thrown would pass 
through when parallel to the pickets, but would be stopped if it landed 
against the fence at right angles to the pickets. 

The reason tourmaline is not commonly used for polarizers is that 
the crystals are yellow in color. Many other crystals which polarize 
light have this drawback or are unsatisfactory in other respects. 

Synthetic Polarizers. All but a few light polarizers in present 
use are made with polarizing sheeting, which is a thin film of plastic 
containing innumerable polarizing elements (either crystals or 
molecular chains) . These are entirely invisible and the film appears 
to be clear and homogeneous. The elements are aligned parallel to 
one another so that they reinforce one another's polarizing effect. 

In 1852, the English physician, W. B. Herapath, discovered a syn- 
thetic crystalline material which transmits polarized light of all 
colors with high relative intensity. Chemically, this material is 
known as sulphate of iodo-quinine. 

These crystals were so unstable mechanically as to shatter into a 
useless powder at the slightest impact, and those who tried to 
master the technique of handling them reluctantly gave up the re- 

Approximately seventy-five years later, Edwin H. Land solved 
the problem of producing a stable synthetic polarizer. Instead of 
attempting to cover the whole area of a polarizer with one large crys- 
tal, he conceived of using innumerable little ones packed together 
and imbedding them in a transparent covering material which would 
prevent them from breaking up into a useless powder. 

The search for other polarizing materials is going on continually 
and one of the later developments contains no preformed crystals 
at all. Its polarizing action is based on a linear control of the 



Vol 48, No. 2 



molecular structure of the material, forming a homogeneous and 
haze-free sheet. 

Land has described its manufacture as follows: "In making actual 
polarizing sheets, we create a brush-like structure inside of a plastic 
sheet a clear, tough plastic 
called poly vinyl alcohol. First, 
it is stretched in one direction 
so that the long, tangled mole- 
cules straighten out, all parallel 
to the direction of stretch. The 
sheet is then dipped into a solu- 
tion like the ordinary tincture 
of iodine in your medicine chest. 
The rusty brown iodine is in- *^^^ 

stantly and rather miraculously 

transformed. It now has two FIG. 11. Diagram of maximum polari- 
zation from a reflecting surface, 
different colors. To polarized 

light vibrating in one direction, it is perfectly white and clear; to 
polarized light vibrating in the other direction, it is black. The 
sheet has become a light polarizer." 

FIG. 12. A simple polariscope. 

Photographic Applications. Polarized light is found in Nature on 
every hand. The sheen on water, pavement reflections, window 
reflections, some of the light from the sky these all have polarized 
light in some degree, and the widest present-day application of 

138 J. A. NORLING Vol 48, No. 2 

polarizers in photography is in the control of light reflected from vari- 
ous surfaces. 

Fig. 10 illustrates the effect of reflection of ordinary light from a 
paper surface and printing having a high reflectivity, and the effect 
of using a polarizer to eliminate, or cut down, the polarized glare 
light. This can be done by using a polarizer either over the light 
source or in front of the camera lens when taking a picture. 

The diagram, Fig. 11, shows that glare light has large components 
of light polarized along an axis parallel to the surface, and small 

FIG. 13. Illustrating strain patterns in a photoelastic 

components at right angles to this. To cut out the glare-light com- 
ponents all that is required is a polarizer whose polarizing axis is 
turned at right angles to the axis of the glare-light components. 

In some cases polarizers can be used to great advantage over the 
photolamps, as well as in front of the camera lens, particularly in the 
photography of such things as silverware, glassware and shiny fabrics. 
One advantageous use of polarizers is in the photography of colored 
objects to eliminate parasite reflections that may come from sur- 
rounding objects or surfaces. Objects photographed this way 
usually have richer, truer colors because color-saturated reflections 
are reduced to a minimum. 

One interesting application of dual polarizers is in their use as 
"faders." These can be placed to control the light from photospots 


so as to increase or reduce a modeling light or for special lighting 
effects in wide variety. 

Research and plant control laboratories find many uses for polar- 
izers. Among these are the polarizing microscope, and the polariscope 
for stress analysis using photoelastic models. 

The simplest type of polariscope has two polarizers with a space 
between. Behind them is a light source which can be diffused as in 
the apparatus shown in Fig. 12. 

The polarizing axes of the polarizers are usually crossed at 90 deg. 
The photoelastic model is inserted between the polarizers and strain 
patterns are revealed if any stresses exist in the material. When a 

FIG. 14. An airfoil section in a streaming birefringent 
liquid, showing eddy currents made visible by polarized 

load is applied the strain patterns reveal information that could be 
obtained in no other way. These can be photographed quite easily 
(Fig. 13). 

The reason for these patterns is that the photoelastic material is 
birefringent, or doubly refracting, in the areas under stress. 

Among the plastics suitable for photoelastic models are specially 
aged Bakelite and cast Marbleite. 

Birefringent liquid solutions can be prepared and used in the study 
of fluid flow around models of ship hulls, airfoil sections, and many 
other shapes. E. A. Hauser and Davis Dewey, of Massachusetts 
Institute of Technology, have made some very interesting and 
valuable contributions to the analysis of streaming and formation of 
eddy currents by using a polariscope tank setup. Liquid is pumped 

140 J. A. NORLING Vol 48, No. 2 

through a tank placed between two polarizers and photographic 
records are obtained on color film. High-speed stills are also made 
for purposes of detailed study (Fig. 14) . The solution used by Hauser 
and Dewey consists of suspended particles of Bentonite clay in water. 
To prepare the Bentonite it is first crushed ; then finely powdered, the 
fine powder settled in water to remove gross particles ; the remaining 
water, holding the finer particles in suspension, is run through a centri- 
fuge where the submicroscopic platelets of Bentonite are separated 
for use in the solution. As the fluid is made to stream, the platelets 
align and this causes the solution to become birefringent. 

A piece of quartz may be used to demonstrate the result of bire- 
fringence. The quartz is placed between polarizers. Immediately 

FIG. 15. Illustrating selective birefringence of polarized 
light in quartz. 

the whole quartz glows with a pure solid color. A change in color 
takes place as the angle of the polarizing axis of the front polarizer 
is changed in relation to that of the rear polarizer. 

The quartz does not produce any image doubling, but it does change 
the direction of polarization of the polarized light passing through and 
the changes are different for different colors. 

The diagram (Fig. 15) shows white light entering the first polarizer. 
It emerges as vertically polarized white light. As it passes through 
the quartz, the direction of vibration of each of the colors is turned by 
a different amount. With the polarizing axis of the second polarizer 
set so that it aligns parallel with the direction of vibration of the red, 
the red passes through and the blue and green are blocked. 

Cellophane is a birefringent material. While the effect on polarized 
light passing through differs physically from that of the quartz, it, too, 
shows striking color patterns. Multiple layers of cellophane produce 

Feb. 1947 



multicolored patterns. This phenomenon has been used to create 
beautiful and striking displays. Sheets of cellophane are cut into 
patterns and pasted on glass. This assembly is placed between polar- 
izers. As one of the polarizers is turned the color patterns change. 

This stunt could find a use in the motion picture studio for special 
effects, for instance, in the production of color cartoons. 

Application of Polarizers to Stereoscopy. The projection of 
three-dimensional pictures of outstanding quality has been made 
possible on a large scale by using polarizers. Of course, Polaroid 
viewers must be used to sort out the dual polarized images so that 
each eye receives only the image it would see in normal vision. 


Courtesy, Photo-Technique 
FIG. 16. Diagram of a double projector installation using Polaroid. 

One method successfully used has been by dual projection. In the 
case of motion pictures, two interlocked machines (Fig. 16) have 
been used; also, films can carry pairs of images and be run in a single 
machine. Lantern slides have been projected in dual machines 
(Fig. 17). In dual projection, each lens has its own polarizers. The 
polarizing axis of the left eye polarizer slants 45 deg to the right and 
that of the right eye polarizer 45 deg to the left. Viewers are as- 
sembled with the right-eye polarizer crossed with that of the left eye, 
and vice versa. A metallic surfaced screen is required, preferably a 
sprayed aluminum one. 

Polarized light projection has been used in foreign lands as well 
as in the United States. In Europe they have been limited to small 
screen projection of stills before small groups. So far as can be learned 

142 J. A. NORLING Vol 48, No. 2 

from the available literature, the only large screen use has been in this 
country, where stereo motion pictures and stills have been shown 
on screens up to 15 by 20 ft. It is most likely that more progress has 
been made in the United States in this application of polarizers than 
any where else. 

The Vectograph. To date, the most remarkable development in 
polarizing photo-materials is the Vectograph. The Vectograph 
promises a practicable approach to the simplification and wide use 
of the stereoscopic process. 

FIG. 17. Dual lantern-slide projector for stereoscopic 

In this new film the image itself is a polarizing image. It polarizes 
the light passing through and does so in varying degrees. Fig. 18 
shows a single image Vectograph picture, partially covered by a 
polarizer. In the region outside the polarizer the image is almost 

In the picture the darkest areas are the result 'of almost complete 
polarization. Lighter areas are the result of partial polarization. In 
the white areas, there is virtually no polarization at all. 

Two Vectographs, each having its own picture, can be combined. 
The polarizing axis of one is made to slant at right angles to that of 


the other. By the polarizing filter the pictures can be made to appear 

If a pair of stereoscopic images are printed in this kind of Vecto- 
graphic form we have a method of producing three-dimensional 

In the three-dimensional Vectograph the polarizing axes of the 
stereoscopic images are slanted 90 deg to each other. If the Vecto- 
graph is viewed thro'ugh Polaroid viewers, the scene resolves into a 
natural two-eye view. 

FIG. 18. A single Vectograph image, showing area 
brought to full contrast by a Polaroid filter whose axis is 
set at 9Q deg to the polarization axis of the image. 

It is evident that no special projectors are required for Vectograph 
films, the only special requirement being the screen. Incidentally, 
a large percentage of this country's theaters are equipped with so- 
called "silver screens" which are perfectly suited to the projection of 
polarized light images. 

Vectographs can be made as reflection prints of large size as well 
as small. They were widely used by America's armed forces and a 
rapidly growing peacetime use for commerce and industry is in 

A fascinating application of the stereoscopic process is in three- 
dimensional drawings. Many of these have been made and they are 

144 J. A. NORLING 

truly intriguing. John T. Rule, of Massachusetts Institute of Tech- 
nology, can be credited as the pioneer in this field. 

The three-dimensional animated cartoon may some day afford 
hilariously exciting moments for millions. For the historian who 
records the first of such events, I believe the birth of the three-di- 
mensional cartoon to have been early in 1939, when Walter Ball, 
of our studios, animated a few short scenes for a three-dimensional 
movie made for an exhibitor at the New York World's Fair. 

Now I should like to make a few predictions. The first is: Light 
control through polarization will find increasing use in photography, 
and uses not dreamed of today will enable photographers to devise 
new forms of pictorial expression. Second: Special lighting equip- 
ment, employing polarizers, will be developed to meet demands for 
new and improved lighting effects. Third: Polarized light control 
will make possible the three-dimensional film for which the motion 
picture industry has been waiting. And finally : Polarized light 
control in electronic picture reproduction will bring three-dimensional 
pictures to the television screen. 



Those of you who were present at the Technical Conference of the 
Society of Motion Picture Engineers, held October 1945 in New York, 
may have heard the several excellent papers presented on the char- 
acteristics and early tests of the RCA IP 37 blue-sensitive photocell. 
This cell was developed at the request of several of the color-film 
companies to reproduce the dye-image sound tracks which will be 
associated with certain color motion pictures. These papers ap- 
peared in the May 1946 issue of the JOURNAL. 

To review the problem briefly, it is well known that the silver-image 
tracks associated with all of the black-and-white pictures and at 
least one type of color picture, Technicolor, reproduce satisfactorily 
on the caesium-silver-oxygen photocell which is universally used for 
sound reproduction in theaters. Certain other color processes, how- 
ever, find it advantageous to use a color sound track or a track which 
is a combination of colors. 

Most of the dyes used for color tracks are relatively transparent 
to the infrared light which is emitted by the ordinary tungsten- 
filament exciter lamp in the sound head. This means that the photo- 
cell current is only weakly modulated by the dye-image, but scratches 
and dirt modulate it almost as much as they would through clear 
film. The IP 37 cell contains a blue-sensitive surface which does not 
respond at all to infrared light. It is being considered as a possible 
replacement for the caesium or red-sensitive cell, as it will reproduce 
both silver-image and dye-image sound tracks. 

In July 1946, the Research Council of the Academy of Motion 
Picture Arts and Sciences established a subcommittee of its Basic 
Sound Committee called the Photocell Subcommittee. It was 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
.* * Chairman, Subcommittee on Photocells, Research Council, Academy of 
Motion Picture Arts and Sciences, Hollywood. 


146 L. T. GOLDSMITH Vol 48, No. 2 

charged with investigation of the desirability and practicability of 
replacing the red-sensitive cell in theaters with the blue-sensitive 
cell. If the change could be recommended, the committee was to be 
sure that the blue cell gave satisfactory results with the dye-image 
tracks and, just as important, it was to make certain that the black- 
and-white or silver-image track would suffer no loss in the change. 

On the committee are representatives of all of the interested color 
companies, several of the film laboratories and sound-equipment 
manufacturers, the major theater service organizations, and repre- 
sentatives of the studio sound departments. The members from the 
color companies are making certain that their test material is repre- 
sentative of their latest color processes, and are advising the com- 
mittee on future trends in sound track. This is particularly impor- 
tant as certain compromises in the make-up of the track may have to 
be made. 

The representatives of the theater service organizations are ad- 
vising us on the problems which might be encountered in the theaters 
during the changeover. The questions of whether there is adequate 
gain in the various amplifier systems, whether older systems can be 
simply and inexpensively modified to take the blue cell, whether the 
older optical systems are sufficiently well corrected in the blue por- 
tion of the spectrum, and so on, are under study. The studio repre- 
sentatives are interested in the problem of quality control in color 
tracks as well as the problems in the theater. All concerned are 
working together to arrive at a conclusion as quickly as possible with- 
out overlooking any factors which might prove embarrassing in the 

The committee is attacking the problem on three fronts simul- 
taneously. With the help of RCA and Western Electric, it is pre- 
paring test material in the form of recorded sound-track negatives. 
These are both variable-area and variable-density tracks which will 
be processed and printed by the color companies and the black-and- 
white laboratories. The test negatives will supply comparative data 
when reproduced on both the red and the blue cells as to sound out- 
put level, signal-to-noise ratio, high-frequency loss, gamma or relative 
level change, harmonic distortion, and cross-modulation and inter- 
modulation distortion. In the case of variable-area track, a direct 
positive is being supplied as well. 

In addition to the measured test data, listening tests are being made 
on a variety of representative samples of color track which are run in 


comparison with the Academy Theater Test Reel on both types of 
cells. Record is being kept on the relative reproduced volume, quality, 
and surface noise of the samples. The tests are made on various types 
of reproducing equipment with cells which are' representative of their 
type, and the results are judged by a fairly large group of listeners. 
No comparison or comment is made on the quality of the picture, as 
this is not within the scope of the committee. 

Meanwhile, a limited number of theaters have been equipped 
with the blue cells and the theater service groups are reporting on their 
performance in the field. 

Not only are valuable performance data being gathered on. the 
photocells, but these tests and comparisons are of value to the color 
companies in maintaining quality control of their product. I cannot 
speak too highly of their co-operation and guidance. 

The committee is not yet prepared to make any recommenda- 
tions with regard to the cell. Color sound tracks representative of 
Ansco Color, Cinecolor, and several types of Magnacolor have been 
reviewed in addition to those with black-and-white tracks. The 
purpose of this preliminary report is to acquaint you with the exist- 
ence of this committee, and to assure you that any data relative to 
the reproduction of existing or proposed color sound tracks would be 


Summary. This paper describes a new 3 5 -mm film recorder designed to meet 
the operational and performance requirements of the major Hollywood studios. Fea- 
tures which simplify operating the machine are described. Serviceability has been 
stressed throughout the design, and the many figures illustrate what has been accom- 
plished. Performance compares favorably with any recorder yet built, and values of 
flutter are presented. 

The PR-31 recorder has been designed to provide the motion pic- 
ture industry with an improved de luxe film recording machine. 
Chief features of the design are improved performance, thoroughly 
dependable operation, sturdy construction, and accessibility for 

In designing this recorder, consideration was given to a great many 
factors, among them the following : 

(1) Dependable performance 

(2) Simplified and convenient operation 

(3) Low flutter 

(4) Low maintenance and ease of servicing 

(5) Quiet operation 

(6) Simplified gearing and general construction 

(7) Beltless take-up 

(8) Ease of adding accessories 

(9) Long life 

(Iff) General appearance 

Because of the many factors involved, no significance should be 
attached to the relative importance of the considerations as listed. 

Keeping in mind the considerations indicated, the recorder (Fig. 1) 
as designed consists of the following units : 

(4) A base assembly containing the plugs, electrical control equipment, and 
carrying handles 

(B) A head assembly containing the film drive and handling equipment 

* Presented Oct. 24, 1946, at the SMPE Convention in Hollywood. 
* * RCA Victor Division, Radio Corporation of America, Hollywood. 



(C) An optical system 

(D) A counter assembly 

(E) A driving motor synchronous or Selsyn 

(F) A gear reduction unit 

(G) A take-up and holdback assembly 
(H) A compartment for accessories 

(/) Covers for the optical system and driving mechanism 

In addition, all provisions have been made for the easy installation 
of a photographic slater and solenoid punch. 

FIG. 1. PR-31 de luxe recorder less magazine. 

The machine is 28 in. long, 18 3 /4 in. deep, and 29 in. high with the 
magazine in place, and weighs approximately 175 Ib. The magazine 
used is the Bell and Howell type. Other type magazines could be 
used with a suitable magazine adapter. 

The base is finished deep umber gray and the units above the base 
are finished light umber gray, both metalustre wrinkle. The control 
panel and trim are finished satin chrome. 

The base, as well as all other structural castings, is made of stabil- 
ized magnesium alloy. This alloy has been selected because of several 
important characteristics including : 

(.4) Light weight (specific gravity 1.8 as opposed to 2.8 for aluminum alloy) 

(B) Excellent machining characteristics 

(Q High damping capacity as compared with other light alloys 

150 M. E. COLLINS Vol 48, No. 2 

The base assembly (Fig. 2) contains the plug panel, the control 
panel, and most of the electrical equipment. The casting is equipped 
with built-in drop- type handles and shear-type resilient mounts. 
The mushroom heads of the resilient mounts may be removed and 
replaced with hold-down bolts so that the recorder can be bolted to 
a frame for truck use while retaining the resilient mounting feature. 

A special nichrome rheostat, edge-wound and continuously vari- 
able, is provided on the control panel for controlling the recording 
lamp. This rheostat provides stepless lamp control and is used as a 
vernier. A series dividohm is provided and adjusted at time of in- 
stallation for dropping the lamp voltage to within the range of the 



FIG. 2. PR-31 base and wiring. 

lamp rheostat. A lamp holding circuit is provided for reducing the 
lamp current to approximately one-half recording value between 
takes. This circuit is relay operated from the motor circuit and is 
arranged so that it is not possible to record with reduced lamp cur- 
rent. A manual switch is also provided in order to check light in- 
tensity without running the recorder. 

The same relay is used to disconnect the slater and punch circuit 
automatically when the recorder is operating. 

The head assembly, shown in Fig. 3, contains all the film driving 
and handling equipment except the motor and the reduction gear box. 
A vertical casting wall divides the filni compartment from the drive 
equipment. The film compartment is extra large and is equipped 


with a light-tight door with a positive lock (Fig. 4) . Lubrication of all 
gears and shafts is by wick feed from one central oil reservoir. 

The film drive consists of a driven 32-tooth sprocket, a magnetic 
drive, two sprung rollers, and sprocket pad rollers; the sprung rollers 
are provided with position stops. Threading is done with one roller 
in its normal position as held by its spring and with the other roller 
held against its stop opposing the spring action. The pad rollers, 
kept in position against the sprockets by detent plates, are held open 
for threading by spring action. The recording drum is provided with 

FIG. 3. PR-31 film compartment with slater and 
punch in place. 

a taper of 0.001 in. per in., and a back flange. This arrangement has 
reduced film weave to a negligible value. 

Threading is very simple and the design is such as to provide the 
same length film loop each time the machine is threaded. Damping is 
provided by the magnetic drive. However, both of the sprung arms 
are undamped. The magnetic drive also provides rapid starting and 
film stabilization so that recording may begin within three seconds 
after starting the recorder. The magnetic drive has been designed 
to provide a maximum of one per cent overdrive and is not critical to 
field current. A change in field current from 1 .0 to 2.0 amp necessarily 
increases the damping, but makes no material difference in the per- 
formance of the machine. The bronze bearing used with the recording 

152 M. E. COLLINS Vol 48, No. 2 

drum is provided with a bearing heater and a thermostat set at 75 F. 
This permits the use of a precision sleeve-bearing with the drumshaft 
without the necessity of a bearing warm-up period. The heater and 
thermostat are located in the head casting below and above the 
drumshaft bushing. The heater is operated from the 220-v motor 
supply when a synchronous motor is used. When the recorder is 
driven by a Selsyn motor, the heater is operated from an auxiliary 
110-v supply. 

FIG. 4. PR-31 rear view, cover removed. 

Fig. 4 shows that the take-up assembly is mounted to the head 
assembly and is driven by a silent chain from the head gearing. A 
holdback device for the feed side of the magazine is provided. Both 
the holdback and the take-up are easily adjusted; the take-up drive 
chain is provided with an adjustable chain tightening shoe. 

The accessory compartment, located to the right of the film com- 
partment seen in Fig. 1, houses the footage counter and provides 
storage space for operating and maintenance items. 

The optical system compartment is equipped with a hinged door 
through which all normal operating adjustments are made to the 
optical system. However, the complete optical system housing is 
removable by loosening two thumbscrews located in the compartment. 


The door is equipped with an opening for observing the visual moni- 
tor, a plunger for operating the illumination meter, and an opening 
for operating the film punch and slating device which is available 
as accessory equipment. Terminal boards have been located in the 
optical system compartment for the purpose of connecting the 
optical system, bearing heater, and the slater and punch assembly to 
the base wiring. 

Controls for the photoelectric cell monitor are also located in the 
optical compartment. 

FIG. 5. PR-31 rear view, magazine in place. 

The back cover, Fig. 5, removable by releasing two thumbscrews, 
completely encloses the rear of the machine. A recess is provided 
in the end of this cover for the motor handwheel. The machine has 
been designed so that either the optical system cover or the rear cover 
may be removed independently of each other. 

. Both Selsyn and synchronous motors are available and all recorders 
are wired for either type of operation. The synchronous motor used 
is a 6-pole, resilient mounted unit designed with a split winding so as 
to provide soft starting without the use of auxiliary starting equip- 
ment. A 6-pole synchronous motor is used; therefore, it is not 
necessary to change any gears when changing from synchronous to 

154 M. E. COLLINS Vol 48, No. 2 

Selsyn drive of the same frequency. When changing from 60-cycle 
to 50-cycle operation, it is necessary to change the reduction gear box. 
This gear reducer is used to eliminate high-speed gearing from the 
recorder head proper and to simplify frequency conversion. A mul- 
tiduty motor is also available if this type of operation is required. 

As standard equipment the recorder is provided with the following 
desirable features in addition to the so-called essentials for a satis- 
factory machine : 

(2) A helical edge- wound nichrome rheostat 

(2} An illumination meter 

(5) A lamp holding device 

(4) A bearing heater 


' v 1 / REFLECTOR n FiLT " r ~~ 

-- - 


FIG. 6. PR-31 basic optical schematic. 

Accessory Equipment. As accessory equipment we have pro- 
vided a photographic slater and solenoid punch shown on the 
slides and a photocell monitor. 

Optical System. The optical system of new design, seen sche- 
matically in Fig. 6, provides for visual monitoring as standard 
equipment and photoelectric cell monitoring may be added without 
any machining. Additional hand room has been provided by 
relocation of the recording lamp and the shutter which is now located 
adjacent to the recording slit. The visual monitor adjustments and 
the shutter adjustments have been greatly simplified. The recording 


lamp is a prefocused 10.5-v, 7.8-amp, curved, coiled filament lamp. 
The lamp socket is provided with the necessary vernier adjustments. 
An improved modulator has been used. The area-type optical system 
is extremely flexible in application and may be supplied for any of the 
listed types of recordings : 

(A) Standard area 

(B) ' Class B push-pull 
(Q Class A push-pull 
CD) Class AB push-pull 
() Double width recording 
(F) Direct positive 

A variable intensity type optical system can be provided if de- 

Performance. The film motion, even better than that of pre- 
vious RCA recorders, compares very favorably with any film re- 
corder yet built. 

The total flutter for all frequency bands is not greater than 0.05 
per cent. The high-frequency component and all 96-cycle disturb- 
ances have been reduced to a negligible value. The low-frequency 
flutter has been reduced to an even lower value than that obtained 
with the PR-23 recorder, which was remarkably free from low-fre- 
quency flutter. 

In addition to these desirable features, the entire construction of 
the recorder is sturdy, assuring long, trouble-free operating life. 

Conclusions. In the design of this recorder every consideration 
has been given to the problems of operation and maintenance. 
In this connection, additional hand room in the film compartment has 
been provided and threading has been simplified as much as possible. 
All parts have been ruggedly designed. Adjustments have been 
eliminated wherever feasible, though all necessary adjustments have 
been retained and made as accessible as possible. For example, 
the magnetic drive brushes are accessible from the film compartment 
and the pad roller-sprocket clearance is a simple screwdriver adjust- 

We believe that the PR-31 recorder will meet studio requirements 
for a de luxe recording machine that combines improved performance, 
ease of operation and maintenance, and a maximum of desirable fea- 
tures v 

156 M. E. COLLINS 


Dr. J. G. FRAYNE: I notice you have included a photocell monitor. Is a visual 
monitor also provided? I did not see it on the optical schematic. 

MR. COLLINS: Yes, Dr. Frayne, a visual monitor is standard equipment as it 
has been with previous RCA recorders. The photoelectric cell monitor is con- 
sidered as accessory equipment and will not be supplied as standard, but it will 
be available and can be added to the machine. In the design of the optical sys- 
tem, all steps have been taken so that the addition of the photocell monitor be- 
comes a simple field installation. 

DR. FRAYNE: Is the addition of photocell monitoring based on customer re- 
quirements or sound engineering, or both? 

MR. COLLINS: We feel that the photocell monitor is a useful tool and It is one, 
I am sure, which some customers, some licensees, will want to make use of ; we are 
making it available for any or all who wish to use it. 

Dr. MARVIN CAMRAS: Do you have figures on the over-all flutter? 

MR. COLLINS: Yes, I have some figures on over-all flutter. I stated ==0.05 
per cent maximum or total flutter. This matter of flutter is sort of a touchy sub- 
ject, as you appreciate. Flutter just as a value does not mean too much. First 
of all, you have to set up a definition for flutter, and after the definition has been 
established it then becomes necessary to tie down the method of measurement, and 
the equipment used for measuring. In other words, I would not be too concerned 
about a figure representing the percentage of flutter unless this figure could be 
compared to the figure obtained from another recording machine when the same 
measuring equipment had been used for both machines. 

MR. JOHN HAWKINS: I do not know whether this is the time and place to dis- 
cuss this aspect of flutter question, but I know some definitions say just 0.05, some 
say the 0.05. Does the plus or minus case correspond to 0.1? 

MR. COLLINS: Plus or minus is the type of flutter definition that everyone in 
Hollywood is using, whereby the measured deviation is plus or minus and not the 
total deviation. 

MR. HAWKINS: Is that rms or peak flutter usually as we express it? 

MR. COLLINS: The ratings that we are giving here represent peak value. 

DR. FRAYNE : I think I can amplify your remarks, Johnny, by saying that the 
0.05 actually means 0.05, not 0.1. The variation is actually either way. 

MR. J. W. THATCHER : I would like to ask if you can further amplify what you 
meant by driving through magnetic drive? I did not quite follow how you meant 
that drive to be accomplished. 

MR. ^COLLINS : First of all, the magnetic drive is a type of drive whereby we 
have a rotating electromagnet. The field coil and the magnetic structure are gear 
driven. It is a little difficult to see that structure (referring to the slide), but it is 
immediately behind the flywheel and is driven by the gear train of the recorder. 
The flywheel itself is connected mechanically to the recording drum shaft, and is in 
no way connected to the gear train. The recording drum and flywheel are driven 
by the flux setup in the air gap of the rotating magnetic structure, the flywheel 
having a copper ring which runs in the air gap of the driven rotating magnet. 
Therefore, we refer to this flywheel, or drum shaft, as being magnetically driven, 
and we call it the RCA magnetic drive. 


Summary. The new Mitchell 16-mm camera has been designed as an all- 
purpose double-system camera, suitable for high speed or sound when used in a blimp. 
This paper describes briefly some of the features incorporated in the new camera. 

The expanding fields of 16-mm film used in advertising, science, 
education, and television have created a demand for a strictly 
professional 16-mm camera. To satisfy that demand, the Mitchell 
Camera Corporation has designed a 16-mm camera along the lines 
of their 35-mm models. 

Diversified production and limited budgets call for an all-purpose 
camera, operating equally well either on high or low speeds and quiet 
enough when housed in a blimp to meet the present requirements of 
sound. Special effects, too, are an all-important factor demanding 
perfect registration for multiple exposure work and ease in lining up 
all types of trick shots. As positive registration requires two pilot 
pins, it is necessary to use double perforated negative in the camera. 

The features of the Mitchell 16 are very similar to the features of 
the 35-mm camera . They include : 

A positive register pin movement ; 

Means for focusing without disturbing the lens position ; 

A shutter opening of 175 deg; 

Frictionless light trap for magazines; 

Veeder footage and frame counter; 

Automatic buckle trip ; 

Large sprocket with safety clutch and a turret to accommodate four lenses. 

By the use of double perforated negative, the established practice 
of a double pull-down claw and standard registration pins can be 
maintained; that is, one pin fits the perforation in both directions 
while the other one acts as a paralleling pin and allows for shrinkage 
of the film. 

* Presented Oct. 23, 1946, at the SMPE Convention in Hollywood. 
* * Mitchell Camera Corporation, Glendale, Calif. 


158 F. F. BAKER Vol 48, No. 2 

The movement is driven by a ball-bearing mounted shaft on which 
are ground two three-point cams, one to actuate the claw while ^ the 
other operates the two register pins. These pins may be withdrawn 
for threading by the rotation of a small knurled cam lock. 

A pressure plate having two bakelite rolls held by hardened and 
ground side rails is set for film thickness, and holds the film in plane 
by a small leaf spring. An extension handle makes it easy to remove 
the pressure plate for cleaning. 

FIG. 1. Three-quarter front view of camera. 

An aperture plate milled from a block of stainless steel is hard 
chrome plated and polished. It is held in place by a cam lock to a 
single stud at the bottom, and a simple guide at the top. It may be 
removed easily for cleaning without the use of tools when the register 
pins are in the threading position. Light baffles are provided around 
the aperture. Two rollers are suitably placed to prevent film loop 

A 20-tooth "dural" feed sprocket is driven through helical gears 
from the shutter shaft. Contained within the sprocket is a clutch 
which governs the tension of the take-up roll. This tension may be 

Feb. 1947 



changed quickly by the use of a scriber or small punch after removing 
one screw. 

Two pairs of film guide rollers hold the film to the sprocket. They 
are disengaged for threading by rotating the knurled eccentric mount. 
There are safety pins which prevent closing the door unless the ec- 
centrics are in place. Strippers top and bottom are provided. 

Magazines are of 400-ft capacity similar to the Mitchell standard 
magazine. They have a roller light trap composed of three velvet 

FIG. 2. Magazines and film moving mechanism. 

rollers. Spindles take the standard film spools. The magazines have 
a corduroy lining, and they are belt-driven. They are relteased by 
pushing a button just inside the door. 

Built into the rear of the camera is a buckle trip switch which 
breaks two lines of the circuit. It may be reset by pressing a button 
on the outside without opening the door. 

The shutter opens to 175 deg by a hand dissolve lever in the back, 
and the shutter may be set in 10 deg steps. A visual miniature 
shutter is seen through a window, and indicates its relation to the film 

160 F. F. BAKER Vol 48, No. 2 

aperture. This greatly facilitates the lining up of projection-back- 
ground shots. 

A Veeder frame and footage counter is mounted in the back plate 
within easy eye position. 

The rack-over of the camera in relation to the base is typically 
Mitchell, as is the erect image focus tube. It is provided with a sliding 
objective giving five or ten times magnification as desired. 

FIG. 3. Rack-over operation and focusing 

Either of two finders is optional. The standard Mitchell erect 
image finder is fitted with a bracket which allows it to be folded up 
out of the way of the door ; or a smaller model may be had which uses 
celluloid mattes. This smaller finder has a focusing mechanism 
actuated by the parallax arm. 

The turret carries four lenses and has a lock operated by a small 
lever near the bottom. 

A completely new set of short focal length B altar lenses has been 
designed by the Bausch and Lomb Optical Company for this camera. 


They consist of 15-, 17. 5-, 20-, and 25-mm lenses having a quality 
equal to anything now used on 35-mm cameras. Lenses above the 
25-mm length will be the same as those now used in professional work. 

Lens mounts are similar to the standard Mitchell, except smaller 
and a finer pitch thread is used in order to obtain the correct amount 
of rotation in focusing. 

A choice may be had in matte boxes; either the Mitchell standard 
with its various holders, or a smaller and simpler version which will 
fill most needs. 

FIG. 4. Camera movement. 

A crank door will be one of the accessories, geared such that when 
the crank is turned at 120 rpm, the camera will be running 24 pictures 
per sec. 

A variety of motors will be available; variable speed, high speed, 
synchronous and interlocking. Their mountings are similar to those 
on the NC model ; that is, integral with the door. 


MR. LLOYD THOMPSON : I would like to ask what percentage of film shrinkage 
a camera will accommodate? 

162 F. F. BAKER 

MR. BAKER: We know that it will handle present tolerances at 140 pictures per 
sec successfully, and the manufacturers, I believe, have expressed their willingness 
to tighten that tolerance at any time. 

MR. H. O. HILLS: Can you tell us where the pilot pins are in this camera rela- 
tive to the picture? 

MR. BAKER: They are the first holes at the bottom of the aperture; that is, 
the top of the projected picture, and they are removed by just one picture from 
the claw engagement. 

MR. HILLS: Is it possible to use present lenses (C mount lenses) on this cam- 

MR. BAKER: The C mount does not fit the present Mitchell. It would take 
an adapter, which could be fitted. 

MR. DAVIS: Is the pressure plate cam operated? 

MR. BAKER: No, it is held by a spring. The plate is set at the thickness of 
film, and it is held there by light pressure sufficient to hold it up. 

MR. JAMES A. LARSON: I would like to know whether the Baltar mount could 
be adapted to a C mount will the Baltar lenses be mountable? 

MR. BAKER: I see no reason why they could not be. 


During the past year the work of the American Standards Asso- 
ciation Sectional Committee on Motion Pictures, Z22, has resulted 
in the reaffirmation of eight Z22 standards and adoption of fifteen 
Z52 War Standards as Z22 standards. This is part of a compre- 
hensive effort by the committee to bring up to date all existing 
standards and consider any meritorious proposals for adoption as 
additional standards. Shortly after the end of the war, the mem- 
bership of the committee was reviewed in order to ensure adequate 
representation by all interested parties. 

A meeting of the committee was held on Oct. 17, 1945, in New 
York to discuss the disposition of existing Z22 standards. It was 
decided to submit the following directly to letter ballot of the com- 
mittee since proposed revisions were minor and were accepted at this 
meeting : 

Z22.2 1946 Emulsion and Sound Record Positions in Camera for 35-Mm 

Sound Motion Picture Film 
Z22.3 1946 Emulsion and Sound Record Positions in Projector for 35-Mm 

Sound Motion Picture Film 
Z22.9 1946 Emulsion Position in Camera for 16-Mm Silent Motion Picture 

Z22.15 1946 Emulsion and Sound Record Positions in Camera for 16-Mm 

Sound Motion Picture Film 
Z22.21 1946 Emulsion Position in Camera for 8-Mm Silent Motion Picture 

Z22.28 1946 Dimensions for Projection Rooms and Lenses for Motion Picture 


Z22.29 1946 Dimensions for Theater Projection Screens 
Z22.31 1 946 Definition for Motion Picture Safety Film 

On the recommendation of a subcommittee, the following Z52 War 
Standards were submitted directly to letter ballot of the committee 
since they had been the subject of extensive study during the war 
and appeared to be suitable for peacetime standards (the newly 
assigned Z22 numbers are given here in place of the Z52 numbers) : 

* American Standards Association, New York; submitted Jan. 13, 1947. 




Vol 48, No. 2 

Z22.401946 Sound Records and Scanning Area of 35-Mm Sound Motion 

Picture Prints 
Z22.41 1946 Sound Records and Scanning Area of 16-Mm Sound Motion 

Picture Prints 
Z22.421946 Specifications for Sound Focusing Test Films for 16-Mm Sound 

Motion Picture Projection Equipment 
Z22.431946 Specifications for 3000-Cycle Flutter Test Film for 16-Mm Sound 

Motion Picture Projectors 
Z22.44 1946 Specifications for Multifrequency Test Film for Field Testing 

16-Mm Sound Motion Picture Projection Equipment 
Z22.451946 Specifications for 400-Cycle Signal Level Test Film for 16-Mm 

Sound Motion Picture Projection Equipment 
Z22.46 1946 16-Mm Positive Aperture Dimensions and Image Size for Positive 

Prints Made from 35-Mm Negatives 
Z22.47 1946 Negative Aperture Dimensions and Image Size for 16-Mm 

Duplicate Negatives Made from 35-Mm Positive Prints 

Z22.48 1946 Printer Aperture Dimensions for Contact Printing 16-Mm Posi- 
tive Prints from 16-Mm Negatives 

Z22.49 1946 Printer Aperture Dimensions for Contact Printing 16-Mm Re- 
versal and Color Reversal Duplicate Prints 

Z22.501946 Reel Spindles for 16-Mm Motion Picture Projectors 
Z22.51 1946 Methods of Making Intermodulation Tests on Variable-Density 

16-Mm Sound Motion Picture Prints 
Z22.52 1946 Methods of Making Cross-Modulation Tests on Variable-Area 

16-Mm Sound Motion Picture Prints 
Z22.531946 Method of Determining Resolving Power of 16-Mm Motion 

Picture Projector Lenses 
Z22.54 1946 Method of Determining Freedom from Travel Ghost in 16-Mm 

Sound Motion Picture Projectors 

All of the above standards were approved by the Z22 Committee, 
confirmed by the sponsor (SMPE), and adopted as American Stand- 
ards during 1946. One of them, however (Z22.29 1946 Dimen- 
sions for Theater Projection Screens), has already been reconsidered 
at the request of the Research Council of the Academy of Motion 
Picture Arts and Sciences and is now in the hands of a subcommittee 
of Z22 for revision. The proposed revision is intended to clear up a 
question as to whether the standard dimensions apply to the entire 
screen or only the portion masked off for the picture. 

Three standards (Z22.101946, Z22.161946, and Z22.221946) 
dealing with emulsion position of 8- and 16-mm films in the pro- 
jector were referred to a subcommittee headed by E. A. Bertram. 
After circulation of the report of that committee and discussion at a 
meeting in Hollywood on Oct. 25, 1946, these standards are about to 
be submitted to letter ballot. 


Two standards were submitted to the Academy Research Council 
for recommendations on revision. One (Z22.32 1941 Fader Setting 
Instructions for Motion Picture Theaters) was recommended to be 
withdrawn by the Research Council. The Z22 Committee concurred 
in this recommendation, which has been forwarded to the sponsor. 
The other standard (Z22.33 1941 Motion Picture Nomenclature for 
Electrical Filters) received an affirmative vote by a majority of mem- 
bers. However, since an objection was raised by several members 
that this standard did not conform with the practice in other indus- 
tries using electrical niters, it was decided to withhold action until 
the matter could be investigated by other ASA committees. 

No action was taken on the following standards since they were so 
recently adopted (1944) : 

Z22.37 1944 Raw Stock Cores for 35-Mm Motion Picture Film 
Z22.38 1944 Raw Stock Cores for 16-Mm Motion Picture Film 
Z22.39 1944 Screen Brightness for 35-Mm Motion Pictures 

The remainder of the Z22 standards of 1944, or previous years, 
were referred to the Standards Committee of the SMPE. This com- 
mittee, under the chairmanship of F. T. Bowditch, has spent a vast 
amount of study on the revision of these 22 standards. Their work 
has already resulted in recommended revisions on the following 
standards which have been sent to letter ballot of the Z22 Committee : 

Z22.5 1941 Cutting and Perforating Dimensions for 16-Mm Silent Motion 

Picture Negative and Positive Raw Stock 
Z22.121941 Cutting and Perforating Dimensions for 16-Mm Sound Motion 

Picture Negative and Positive Raw Stock 
Z22.17 1941 Cutting and Perforating Dimensions for 8-Mm Motion Picture 

Negative and Positive Raw Stock 
Z22.351930 Dimensions for 16-Tooth 35-Mm Motion Picture Projector 

Z22.36 1945 Cutting and Perforating Dimensions for 35-Mm Motion Picture 

Positive Raw Stock 

One proposed standard (Z22.55/44 Specifications for 35-Mm 
Sound Motion Picture Release Prints in Standard 2000-Foot Lengths) 
has been submitted by the Academy Research Council. The pro- 
posed standard is now in use by most American 35-Mm motion pic- 
ture producers. It has been submitted to letter ballot of the Z22 

At the last meeting of the Z22 Committee on Oct. 25, 1946, a sub- 
committee under F. L. Brethauer was set up to study proposed revi- 


sions to Z52.6 1944 Method of Determining Picture Unsteadiness 
of 16-Mm Sound Motion Picture Projectors. Another subcommittee 
under M. C. Batsel was appointed to study suggested revisions of 
Z52.101944 Specification for Buzz-Track Test Film for 16-Mm 
Sound Motion Picture Projectors. A third subcommittee headed by 
J. A. Maurer was assigned to study Z52.7 1 944 Method of Determin- 
ing Uniformity of Scanning Beam Illumination of 16-Mm Sound 
Motion Picture Projectors. The Z52.21944 Specification for Test 
Film for Checking Adjustment of 16-Mm Sound Motion Picture 
Projection Equipment was referred to the Joint Committee on Test 
Films of the SMPE and the Research Council for the preparation 
of a specification to be considered for adoption as an American Stand- 
ard. The Joint Committee on Test Films was also asked to prepare 
a specification for a warble test film. It was further agreed that 
Z52.14 1944, Nomenclature for Motion Picture Film Used in 
Studios and Processing Laboratories, should be submitted to the Z22 
Committee by letter ballot. 

The chairman wishes to take this opportunity to express his ap- 
preciation not only for the work of the members of the committee 
but also for the active co-operation by the Standards Committee of 
the SMPE and the Research Council of the Academy of Motion 
Picture Arts and Sciences. 

C. R. KEITH, Chairman 














The statement that follows is presented as a preliminary report 
from the Committee on Preservation of Film. Its preliminary char- 
acter stems from the fact that the assignment connoted by the title 
of this paper represents a major undertaking, the aftermath of war 
work made certain demands on the work schedules of members of the 
committee, correspondence and travel have been difficult, and as a 
consequence the committee has not been able to complete its work. 
One meeting of the committee was held in Washington on Sept. 27, 
1946, subcommittees have been set up, and the various problems 
before us are being resolved. It is hoped, therefore, that a full and 
useful report may be ready for the 1947 Spring Convention. 

In view of these circumstances the committee has decided to pre- 
sent an outline of the various considerations before it as a means of 
stimulating further discussion and of enlisting any help that others 
may be in a position to give. Here are the considerations: 

(1) The volume of film of a record character has greatly increased 
and is continuing to increase. The Government alone may have some 
300,000 reels of such material set aside for permanent preservation 
within the next few years in the form of motion pictures, to say 
nothing of microfilm, still film, and aerial maps. It has been roughly 
estimated that storage space equivalent to 4000 or 5000 vaults will 
be required for such material. 

(2) Expository film (sometimes referred .to as documentary film) 
for training, teaching, and the dissemination of information, is making 
a major impact on our consideration and the people concerned with 

* Presented Oct. 23, 1946, at the SMPE Convention in Hollywood. 
* * Chairman, SMPE Committee on Preservation of Film; Director, Motion 
Picture Division, The Library of Congress, Washington, D. C. 



such activities not only need help and guidance but are making in- 
sistent demands for such help. 

(3) The great entertainment field as roughly represented by 
Hollywood and related sources is becoming historically minded and 
will not be content in the future to live on a day-by-day or a hand- 
to-mouth basis but is looking both forward and backward on a longi- 
tudinal basis. 

(4) Industrial firms are likewise setting up their own archives and 
need the help and leadership this committee can give in respect to 

(5) Both records and lives are being lost through the use and mis- 
use of nitrate film. 

(6) The National Board of Fire Underwriters, the National Bureau 
of Standards, and this committee need to speak the same language 
and preach the same doctrine in respect to this problem; this is not 
presently the case. 

(7) Standardization of vault construction, laboratory practices, 
and related problems in handling film is badly needed. 

(8) A further investigation of the permanency of color dyes, of 
plastics for a possible new film base, cold lights (mercurial and 
fluorescent) pin-point lights (Zirconium), and rehumidifying tech- 
niques to prevent brittleness of acetate film is indicated. 

(9) In carrying out the work of the committee it seems expedient 
to make contacts with other agencies sharing similar interests and 
responsibility. Therefore, your committee requests authorization 
to make appropriate contacts with the following people : (1) National 
Board of Fire Underwriters, with a view to formalizing its recom- 
mendation covering the size of vents in ratio to the film storage load ; 

(2) Federal Fire Council, seeking its co-operation in giving effect to 
the committee's recommendations, as well as receiving the aid of its 
engineering staff. Note: The Chairman of the Federal Fire Council 
Construction Committee, for example, has recommended such liaison; 

(3) Other committees of the Society, such as the committees on Color, 
Laboratory Practices, Processing Photography, and Standards. 


MR. J. I. CRABTREE: Did you plan to store all this film in Washington or in an- 
other location? 

MR. BRADLEY: Already 81 vaults have been filled at Suitland, Maryland, 
temporary in character and to be torn down. The major storage plant will be at 
Suitland, Maryland, where about seven acres have been set aside by the Govern- 


ment for a $5,000,000 film facility, storage principally. Legislation has already 
been approved by the Senate, and is pending before the House, covering this proj- 
ect. However, we hope that many people will store copies of the same film in 
many parts of the country, because it is only through scattering of records, books, 
and other record material can we hope they will survive another war; bombing 
will be a factor. 

MR. GEORGE TALLIAN: Is there any attempt made at the present time to treat 
film chemically before it is stored, or do you just put it away as is? 

MR. BRADLEY: Attempts are being made and practices are being approved to 
treat the film in the laboratory to bring the salts up to a state of solubility, and 
therefore enable the maximum amount of hypo to be removed; and after that it 
will be a question of housekeeping in terms of temperature and humidity. But the 
question of coating and impregnation, embalming, and other techniques to put on 
the outside of the film has been considered and tested by the Bureau of Standards. 
I find I must be very cautious in what I am about to say because I realize that 
commercial interests are at stake; so I will merely say this: chemically we have 
found that none of those things add to the life of the film. As to mechanics and to 
wear and tear on the film, that is another matter. 

MR. CRABTREE : During your many years of experience at the Archives, what 
percentage of the films have you had to duplicate because of incipient or partial 
decomposition ? 

MR. BRADLEY: I could not give you an exact percentage, Mr. Crabtree, but a 
considerable body of that film has deteriorated in our hands, because we were not 
able to duplicate because of lack of funds, equipment and personnel. We found 
in many cases, when the film was brought out of storage, unwrapped and unwound, 
the moisture in the air immediately precipitated deterioration ; overnight, almost. 
Mr. Gregory, my former assistant at The National Archives, can bear witness to 
this fact. We have developed tempering techniques, bringing the film out and 
letting the temperature rise slowly by radiation. Care should be taken to prevent 
exposure of the film to the ah- until the temperature of the film is in balance with 
the temperature of the air; otherwise, moisture condensation on the surface of the 
film will result. 

MR. CRABTREE: To what extent do you plan to store the film at low tempera- 
tures say around 50 F and to what extent do you plan to isolate the films in in- 
dividual compartments as against mass storage in a unit vault? 

MR. BRADLEY: On the nitrate film of high record value, we intend to store it 
in cabinets, reducing the unit of risk to a minimum, perhaps, one reel instead of a 
vault full of reels. We intend, for the same film of high record value, to maintain 
temperatures of about 50 F and about 50 per cent relative humidity. That is 
about as low a temperature as people can work in. We will have the tempering 
cans in which we will bring the film out of the vaults, set them in the workroom, 
and let radiation lift the temperature so it will be safe to unwind the film. Film 
of less record value can be stored without the cabinets. However, our entire pro- 
gram contemplates the transfer of record film to acetate stock as fast as funds will 
permit, so all of the Government record film will ultimately be on the safety 
stock, which has a much longer life than the nitrate film. 

MR. CRABTREE: Has any estimate been made as to the life of the film in stor- 


MR. BRADLEY: Three to five hundred years for acetate film, at which time it 
can be copied and perpetuated for perhaps three to five thousand years. 

MR. CRABTREE: Has any progress been made in the transfer of images to 
metal films? 

MR. BRADLEY: It does not seem necessary. The only metal used in this con- 
nection above an experimental stage has been aluminum which will pit under the 
influence of sulfur fumes. It also has a bad fault in that it crinkles and has to 
be ironed out. It is also opaque and projection has to be by reflection, but so far 
no other metal has been used widely. When acetate film has preservation charac- 
teristics better than the best rag paper, we do not feel the need for metal. 

MR. CRABTREE : With regard to the vaults at present in The Archives Building, 
are the cabinets of 18-8 stainless steel, and have you observed any corrosion of the 
metal? In other words, will it be necessary to construct them of molybdenum 
stainless steel instead of ordinary 18-8, or what construction material have you 
found most desirable? 

MR. BRADLEY: The cabinets are of molybdenum stainless steel. There has 
been some corrosion on them owing to the fluxing material when they were welded 
and fabricated. However, that is a seepage process, and we believe that that 
seepage will expend itself in a few years. We are simply wiping it off with lemon 
oil and watching it, but the main body of the cabinets themselves seem to be hold- 
ing up nicely. A new cabinet has been developed which is called the Cascade 
Cabinet, previously mentioned in some of our reports, which can be made out of or- 
dinary furniture steel at considerably less cost, and which can be thrown away 
when it rusts over a period of time, and be much cheaper than the stainless steel 
cabinets. The stainless steel cabinets cost us about $30 per reel to put the film 
away. Cabinets for eight vaults (about 2000 rolls) cost us about $60,000, which is 
much above the reach of the average film library. The Cascade Cabinet can be 
built for about $2 per roll (wholesale cost), and by painting and by having proper 
air we feel that they will not rust for over a decade at least ; and at that time, if 
they did rust, new cabinets could be put in. They avoid insulation and other ex- 
cessive expenses. 


A perusal of the occasional JOURNAL issue which records the mem- 
bership of the various committees of the Society shows that the 
Committee on Standards, with approximately 50 members, is the 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
* * Chairman; National Carbon Company, Cleveland, Ohio. 

Feb. 1947 STANDARDS 171 

largest one of all, and that by a substantial margin. Moreover, this 
large membership is not confined to a limited field of interest, as are 
the other engineering committees. On the contrary, every im- 
portant phase of the motion picture industry is represented. The 
reasons for this may not at first be apparent, since the diverse in- 
terests of such a large group would seem to make the study of a single 
subject a very cumbersome procedure. Actually, this is not the case, 
since the entire committee acts as a unit only on matters of general 
policy, and in final balloting on the recotmmendations of its sub- 
committees. It is these subcommittees which do the work, in small 
groups of perhaps a half-dozen individuals, chosen to be representative 
of those phases of the industry directly concerned in the field under 

The large total membership thus acts effectively as a reservoir 
from which capable subcommittees can be drawn; and equally im- 
portant, when the recommendation of a subcommittee is presented 
for final ballot, a completely representative expression of opinion is 
assured which strengthens any Standard that survives such a critical 
review. Other papers scheduled for this Convention make apparent 
the fact that Standards can be a very important factor in the advance 
of a technological industry such as our own. This can only be so if 
these standards are carefully worked out to recognize all points of 
view, so that the industry comes to recognize this fact, and accepts 
the Standards accordingly. The wide representation of your Com- 
mittee on Standards has been chosen with this important end in view. 

Eight subcommittees of the parent committee are active as this 
is written. The work of E. K. Carver's Subcommittee on 35-Mm 
Sprockets (which led to the recommendation of a 0.943-in. diameter 
sprocket giving double the film life obtained with the present 0.935- 
in. sprocket) is being continued, with the objective of recommending 
a more complete revision of the American Standard for 35-mm Motion 
Picture Film, 16-Tooth Projector Sprockets, Z22.351930. Even 
though it is thus agreed that other aspects of this Standard require 
consideration for revision, this will require sufficient time so that the 
parent committee has recommended the immediate revision of the 
diameter specification, giving the industry the benefit of this im- 
portant revision at once. 

Related to this work is that of Otto Sandvik's Subcommittee on 
8-Mm and 16-Mm Projector Sprockets. This is developing into the 
specification of a design-formula, rather than the more conventional 


tabular-type of specification, and has led to the preparation of a 
technical paper for presentation at this Convention under the title 
"Proposals for 16-Mm and 8-Mm Sprocket Standards." 

D. R. White's Subcommittee on Photographic Density and Sensi- 
tometry has completed its consideration of American Standard 
Z22.27 1941 on Photographic Density, and this has been referred 
to the parent committee where a letter ballot is presently being con- 
ducted. The Sensitometry Standard Z22.261941 is still under dis- 
cussion by the subcommittee. 

D. F. Lyman's Subcommittee on Projection Reels is in substantial 
agreement on the draft for 8-mm and 16-mm reels. The 35-mm reel 
specification is requiring more detailed study. 

The Subcommittee on 8-Mm and 16-Mm Camera and Projector 
Apertures under the chairmanship of J. A. Maurer, is considering the 
revision of the six present standards, but has not advanced any of these 
for consideration by the parent committee. 

The Subcommittee on Film Splices, under the chairmanship of 
W. H. Offenhauser, Jr., has submitted an initial report which was 
published in the JOURNAL. 1 A new proposal was published, for a 
trial period of one year, as specified on page 8 of this reference. It 
was agreed by the members of the subcommittee that the war stand- 
ard which formed the basis for this new proposal had not been in 
effect long enough to prove its value. The response to this report, 
while encouraging, is by no means complete, and the subcommittee 
wishes particularly to invite comments by parties interested in this 

Dr. Carver's Subcommittee on Cutting and Perforating Raw 
Stock has completed its consideration for revision of five standards, 
and drafts have been submitted for letter ballot to the parent com- 
mittee. In addition, this subcommittee has just recently been given 
the task of preparing a standard on the cutting and perforating of 
32-mm film. 

Other projects which are being studied with the prospect of early 
subcommittee activity are those for daylight-loading spools and lens 
aperture markings. In the first case, F. L. Brethauer has been ap- 
pointed chairman of a subcommittee to study the standardization of 
daylight-loading spools for 35-mm and 16-mm motion picture film. 
Pending the organization of his subcommittee, he is determining the 
correlation of this project with work previously done by ASA Com- 
mittee Z38 in the preparation of standards for microfilm spools. 


With regard to lens aperture markings, it has been agreed that a study 
should be made of the problem of marking lenses on the basis of meas- 
urements of actual light transmission. The Research Council of the 
Academy of Motion Picture Arts and Sciences and the Society are 
reviewing the prior art in this field to form a sound basis for the new 


1 "Report of the Subcommittee on 16-Mm Film Splices," J. Soc. Mot. Pict. 
Eng., 47,1 (July 1946), p. 1. 



The Theater Engineering, Construction, and Operation Committee 
of the SMPE has been formed for the purpose of rendering to motion 
picture theaters the same type of technical and scientific service that 
the Society renders to the other branches of the industry. 

It is inconsistent that the best scientific and technical skills should 
be concentrated upon the development and manufacture of the 
product, and its end use be left to chance. 

The Film Projection Practice Committee has made a substantial 
contribution to the motion picture theater -through its standards and 
other activities. 

There are, however, many factors other than projection that con- 
tribute to the comfort, enjoyment, and safety of the theater patron 
and the efficiency of theater operation. It is these factors, not 
covered by any other committee of the Society, that the Theater 
Engineering, Construction, and Operation Committee proposes to 

One of the important matters that may come to the committee 
at any time is that of building codes regulating motion picture 

* Submitted Dec. 20, 1946. 
* * Chairman, Paramount Pictures, Inc., New York. 


theaters. There are in development many revisions of existing 
codes, and new codes are being formulated locally from time to time. 
The Building Officials Conference of America is formulating a recom- 
mended national or uniform code, and this organization will, when it 
reaches the theater code, welcome our co-operation. We may thus 
be helpful in developing a code which will combine every element of 
safety and comfort, and at the same time be entirely practicable. 

The committee is "trying its wings" on an investigation of theater 
carpets. This subject might at first glance appear to be of minor 
importance and involve little scientific knowledge. Upon investi- 
gation, however, we find some of the highest technical skills involved 
in the manufacture and development of carpets. We have been in 
contact with the Research Committee of the Carpet Institute of 
America, and may develop substantial improvements through co-op- 
eration with them. 

We find an outstanding need for greater technical skill in the laying 
of carpets and the preparation of the theater by the architect for the 
installation of carpets. We propose to prepare standards for carpet 
installation covering, among other things, recommended thicknesses 
and type of carpet linings for various locations, size and locations of 
insets in floors and steps for securing carpets, types and depths of 
depressions to receive carpet. 

We further propose to develop standards for maintenance and 
cleaning of carpet. 

Enormous amounts are spent by the industry annually for carpet, 
and we are told that adoption of proper practice in selection, installa- 
tion, and maintenance of carpet may prolong its life 25 per cent. 
This would represent a substantial dollar and cents saving. 

We have under way, and practically completed, a study to develop 
an electric heater suitable for motion picture booths. Installation of 
electric heaters in motion picture booths has heretofore been pro- 
hibited. We are about to obtain the approval of the National Board 
of Fire Underwriters, and we trust that the approval of the various 
authorities will follow. 

We also have under way a study of gas or gasoline-driven diesel-type 
generators for theater emergency lighting. These devices have been 
developed to a high degree of effectiveness and reliability. The in- 
dustry has indicated some degree of interest in this development. 

We are seriously handicapped by a lack of clerical and technical 
help. We have already collected more information on the subject 


of theater carpet than, we believe, is available anywhere else. Ar- 
ranging and co-ordinating this information requires more time than 
committee members themselves have available. With some technical 
and clerical assistance we could at this time release some valuable 
information, in tentative form, at least. 


Chicago, Illinois 

April 21-25, 1947 

Officers in Charge 

LOREN L. RYDER ............................ President 

DONALD E. HYNDMAN ....................... Past-President 

EARL I. SPONABLE .......................... Executive Vice-P resident 

JOHN A. MAURER. . ......................... Engineering V ice-President 

M. R. BOYER .............................. Financial Vice-President 

C. R. KEITH ............................... Editorial Vice-President 

W. C. KUNZMANN .......................... Convention Vice-President 

G. T. LORANCE .............................. Secretary 

E. A. BERTRAM ............................. Treasurer 

General Office, New York 
BOYCE NEMEC .............................. Engineering Secretary 

HARRY SMITH, JR ........................... Executive Secretary 

Directory of Committee Chairmen 

Midwest Section and Local Arrangements ..... A. SHAPIRO, Chairman 

Papers Committee .......... . ............... GORDON A. CHAMBERS, Chairman 

R. T. VANNIMAN, Vice-Chairman 
N. L. SIMMONS, Vice-Chairman 
H. S. WALKER, Vice-Chairman 
Publicity Committee ........................ HAROLD DESFOR, Chairman, 

assisted by LEONARD BIDWELL, 
Registration and Information ................ W. C. KUNZMANN, Chairman, 

assisted by E. R. GEIB, G. W. 



Luncheon and Banquet W. C. DsVRY, Chairman 

Hotel and Transportation H. A. WITT, Chairman, assisted 

by C. H. STONE 
Membership and Subscription Committee 

(Midwest Section) 9 TOM RESS, Chairman 

Ladies Reception Committee Hostess MRS. A. SHAPIRO 

Projection Program Committee 35-mm S. A. LUKES, Chairman, assisted 

by Members Chicago Projec- 
tionists Local 110 
16-mm H. WILSON, Chairman 


The management of The Drake, located at Lake Shore Drive and Upper 
Michigan Ave., Chicago 11, Illinois, Convention Headquarters, extends SMPE 
members and guests the following per diem room rates, European plan : 

Room with bath, one person $4 . 55-5. 50 

Room with bath, two persons, twin beds $7.50-8.50-9.00-10.00-12.00 

Parlor suites with connecting bedrooms, two persons.$18 . 00-20 . 00-22 . 00-25 . 00 

Note. Room accommodations must be booked early and direct with W. M. 
Cowan, Assistant Manager, The Drake, prior to April 15. When making 
reservations be sure to advise Mr. Cowan that you are attending the SMPE 61st 
Semiannual Convention. No rooms will be assured or guaranteed at The Drake 
unless confirmed. 


With travel conditions still not normal, the Eastern and West Coast members 
who are contemplating attending the 61st Semiannual Convention should consult 
their local railroad, Pullman and plane agents regarding effective schedules and 
rates at least 30 days prior to your departure. 


The Convention Registration Headquarters will be located in the French Room 
Foyer of The Drake. Members and guests are expected to register. The fee is 
used to help defray the Convention expenses. 


Members and others who are contemplating the presentation of papers at the 
Chicago Convention can greatly assist the Papers Committee in the early schedul- 
ing and assembly of the program by mailing in the title of paper, name of the 
author, and an abstract to the Papers Committee Chairman, or to the Society's 
offices in the Hotel Pennsylvania, New York, not later than March 15. Complete 
manuscripts must be received by April 7 to be included in the final program. 
Your co-operation in this regard is solicited. 

The Convention business and technical sessions will be held in the Grand Ball- 
room located on the lobby floor of the hotel. 



The usual Get-Together Luncheon will be held in Gold Coast Room on Monday, 
April 21, at 12: 30 P.M. 

The luncheon program and eminent guest speakers will be announced in later 
bulletins. Guaranteed seating at the luncheon will be assured only if tickets are 
procured prior to 11:00 a.m. on April 21. Assist the Committee and hotel in pro- 
viding accommodations by complying with this request. 


The SMPE 61st Semiannual Banquet and social get-together will be held in the 
palatial Gold Coast Room of The Drake on Wednesday evening, April 23, at 8:00 
P.M. (Dress optional.) 

A Cocktail Hour for holders of Banquet tickets will be held in the French 
Room preceding the banquet from 6:46 to 7:45 P.M. 

Banquet tickets should be procured and tables reserved at the Registration 
Headquarters prior to noon on April 23. The Banquet program will be announced 
in later bulletins. 

Luncheon and Banquet tickets may be procured in advance of the dates of these 
functions through W. C. DeVry, Chairman of the Luncheon and Banquet Com- 
mittee, located in Chicago, or through W. C. Kunzmann, Convention Vice- 
President, who will be at The Drake several days prior to the opening date. 

Note. All checks or money orders issued for registration fee and luncheon or 
banquet tickets should be made payable to W. C. Kunzmann, Convention Vice- 
President, and not to the Society. 


Ladies attending the Convention should register with Mrs. A. Shapiro, the 
hostess, and members of her Committee in their headquarters, Parlor H , which is 
adjacent to the Grand Ballroom where the Convention sessions will be held. 

Ladies' entertainment program will be announced later by the Ladies Com- 


Convention recreational program will be announced later by the Local Arrange- 
ments Committee. Consult the hotel bulletin board or Registration Head- 
quarters for other local amusements available in Chicago during the Convention 


Convention identification cards will be honored through the courtesy of the 
Balaban and Katz Corporation at the following deluxe theaters located in the 
Loop, namely: Chicago, State Lake, and United Artists Theaters. 

The H. and E. Balaban Corporation extends their courtesy and will honor these 
cards at their Esquire Theater located in the immediate vicinity of The Drake 

RKO Theaters (Chicago Division) extends their courtesy of honoring the Con- 
vention identification cards at their deluxe RKO Palace and Grand Theaters, 
located in the Loop. 



Monday, April 21, 1947 

Open Morning. 
9:30 a.m. French Room Foyer: Registration. Advance sale of Luncheon and 

Banquet tickets. 

12: 30p.m. Gold Coast Room: Get-Together Luncheon (Speakers). 
2:00 p.m. Grand Ballroom: Business and Technical Session. 
8:00 p.m. Grand Ballroom: Evening Session. 

Tuesday, April 22, 1947 

9: 30 a.m. French Room' Foyer: Registration. Advance sale of Banquet 


10:00 a.m. Morning Session: Location to be announced later. 
2: 00 p.m. Grand Ballroom: Afternoon Session. 
Open Evening. 

Wednesday, April 23, 1947 

9:30 a.m. French Room Foyer: Registration. Advance sale of Banquet 

10:00 a.m. Morning Session: Location to be announced later. 

Open Afternoon. 

8:00 p.m. Gold Coast Room: SMPE 61st Semiannual Banquet and evening 
for social get-together will be held in the palatial Gold Coast Room 
(dancing and entertainment). Cocktail Hour for holders of ban- 
quet tickets, 6:45-7:45 P.M. The program for this evening will 
be announced later by the Banquet Committee. Tables may be 
reserved at the Registration Headquarters prior to noon on April 

Note. The Registration Headquarters will be open on this afternoon for those 
desiring to make final arrangements for the Banquet. 

Thursday, April 24, 1947 

Open Morning. 

2: 00 p.m. Grand Ballroom: Afternoon Session. 
8:00 p.m. Grand Ballroom: Evening Session. 

Friday, April 25, 1947 

10: 00 a.m. Grand Ballroom: Morning Session. 
2: 00 p.m. Grand Ballroom: Afternoon Session. Adjournment of the 61st 

Semiannual Convention. 

Note. All sessions during the five-day Convention will open with an interesting 
motion picture short. 



Book your room accommodations early and direct with W. N. Cowan, Front 
Office Manager, The Drake, Chicago, Illinois. All reservations are subject to 
cancellation prior to April 10. 

Co-operate with the Luncheon and Banquet Committee by procuring tickets 
well in advance of the dates for these functions, so that hotel arrangements can be 
made accordingly. 

This is a tentative schedule and is subject to change. 

Convention Vice- President 



Marvin Camras, of the Armour Research Foundation, Chicago, discussed 
magnetic sound for motion pictures before the Atlantic Coast Section of the 
Society at a meeting held on January 16, 1947. Mr. Camras described the prin- 
ciples of sound recording using a material having magnetic properties coated in a 
matrix onto motion picture film. 

The recording and reproduction of sound is carried out by point-to-point 
magnetization of the material. The coating can be applied in various ways such 
as, for instance, to the edge of motion picture film already completed, or in a 
form that will produce multiple sound tracks for sound use only. 

A portion of the presentation was conducted by the use of a recorded track on 
film. Demonstrations were also made of sound quality and the wire recorder 
developed by the Armour Research Foundation was also shown and demonstrated. 

The discussion period following presentation of the paper brought out many 
interesting points. About 300 members and guests attended the meeting, held 
in the Salle Moderne of the Hotel Pennsylvania, New York. 


Capt. William C. Eddy, director of television station WBKB, Chicago, spoke 
on "Recent Developments in the Field of Television" at the January 9, 1947, 
meeting of the Midwest Section of the Society in Chicago. Capt. Eddy based 
much of his talk on material collected in the operation of station WBKB, stating 
that there are 853 sets in the telecast area of Chicago with average audiences of 
eleven persons per set (72 per cent of the sets are in private homes). During 
1946 station WBKB was on the air 1088 hours, and a total of 77 motion picture 
films was shown in December 1946. 

Coleman lanterns were used during the coal strike for street telecasts, although 
incandescent light is generally preferred. Other aspects of television operation 
were discussed including programming, relay systems, color, studio equipment, 
and audiences. A lively question period was enjoyed, with such subjects as 
screen brightness, resolution, screen life, and contrast control being discussed. 



A Committee on Nominations has been appointed by President Ryder, in ac- 
cordance with By-Law VII of the Constitution and By-Laws, to recommend 
nominations for offices expiring December 31, 1947. General elections are held 
prior to the October convention; offices expiring and incumbents are given 
on the reverse of the contents page of this issue of the JOURNAL. 

Voting members of the Society (Honorary, Fellow, and Active) are invited to 
submit recommendations for candidates to the Nominating Committee, sending 
names to the Chairman, E. A. Williford, 230 Park Ave., New York 17, N. Y., 
or to members of the committee as follows: Emery Huse, E. I. Sponable, H. W. 
Moyse, J. W. Boyle, E. W. Kellogg, K. F. Morgan, J. K. Milliard, and M. G. 
Townsley, whose addresses are given in the last Membership Directory. 

Only Honorary, Fellow, and Active members may hold office. A report of the 
Nominating Committee will be submitted to the Board of Governors at the July 
1947 meeting. 


The first meeting of the Pacific Coast Section of the Society in 1947 under W. V. 
Wolfe, chairman-elect, opened with a paper by F. E. Carlson on "Flashtubes, 
A Potential Illuminant for Motion Picture Photography," read by Ralph E. 
Farnham on January 17. Tlie paper presented a preliminary appraisal of flash- 
tubes from the point of view of motion picture studio photography. Such 
sources have been widely and successfully used for still photography for several 
years. In this field the short duration and high intensity of the flash, its color 
quality and high efficiency have been important factors in its favor. Most of 
these advantages, while equally important in the motion picture studio, cannot 
necessarily be realized to the same degree in this field. 

There remain many problems in the use of flashtubes, the magnitude of which 
cannot be predicted at this time, and will undoubtedly require thorough analysis 
before a final evaluation is possible. 

This paper will appear in the JOURNAL at an early date. Much interest was 
shown in the discussion period by the large group of Section members and guests 
present in the review room of Electrical Research Products Division of Western 
Electric, Hollywood. 

, cUto* ojtite Motto*. Picture. aX&uM, 

f'TAc Technique of Motion Picture Production is the 
first unified presentation of modern technical practices 
in motion picture production . . . Compact and com- 
plete ... In plain terms that any interested layman can 
understand. . . 

f "This volume is indicated on the desk of anybody who 
wants to know about the motion picture and how it is 



I Technology in the Art of Producing Motion Pictures 

v ........ Leon S. Becker 

II Cinematography in the Hollywood Studios: 

Black and White Cinematography John W. Boyle 

Putting Clouds into Exterior Scenes Charles G. Clarke 

Technicolor Cinematography Winton Hoch 

III Special Photographic Effects Fred M. Sersen 

IV Re-Recording Sound Motion Pictures L. T. Goldsmith 

V The Technique of Production Sound Recording . . Homer G. Tasker 

VI Prescoring and Scoring Bernard B. Brown 

VII Illumination in Motion Picture Production 

. . .R. G. Linderman, C. W. Handley and A. Rodgers 

VIII The Paramount Transparency Process Projection Equipment. . . . 

Farciot Edouart 

IX Motion Picture Laboratory Practices James R. Wilkinson 

X The Cutting and Editing of Motion Pictures. .Frederick Y. Smith 
XI The Projection of Motion Pictures Herbert A. Starke 

Price $4.50* 

Each section written by a specialist in the motion picture industry. . . Authentic infor- 
mation on various technical problems of motion picture production. ... A useful and 
valuable reference for technicians, students, librarians, and others desiring technc- 
logical data on the motion picture .industry compiled in one volume. 

Published for the Society of Motion Picture Engineers by Interscience Publishers, Inc., 
215 Fourth Avenue, New York 3, N. Y. 

* 20% discount to members in sood standing if ordered throush SMPE. Orders must be accompanied 
by check or money order, and include 2% sales tax if delivered in New York City. 


Vol 48 MARCH 1947 No. 3 



Statement of SMPE on Revised Frequency Allocations 183 

Report of the General Secretary, 1946 203 

A New Series of Camera Lenses for 16-Mm Cinematog- 
raphy W. B. RAYTON 211 

Wilbur B. Ray ton I. L. NIXON 217 

The Soundman G. R. GROVES 220 

The Development of an Invisible 16-Mm Film Splice 


A New Motion Picture Film Splicer I. I. MERKUR 238 

Blueprinting the Classroom Film F. S. CELLIER 243 

Corrective Networks F. L. HOPPER 253 

A Projection Reel of Improved Design E. S. MILLER 261 

Current Literature 269 

Society Announcements 271 

Copyrighted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 










** President: LOREN L. RYDER, 

5451 Marathon St., Hollywood 38. 
**Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
**Executive Vice-President: EARL I. SPONABLE, 

460 West 54th St., New York 19. 
^Engineering Vice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial V ice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
* Financial Vice-President: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** 'Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
^Treasurer.: E. A. BERTRAM, 
850 Tenth Ave., New York 19. 


**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 5451 Marathon St., Hollywood 38. 
*fjAMES FRANK, JR., 356 West 44th St., New York 18. 

*JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*tA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
*WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

*Term expires December 31, 1947. tChairman, Atlantic Coast Section 
**Term expires December 31, 1948. TChairman, Midwest Section. 
* Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 
their annual membership dues; single copies, $1.25. Order from the Society at address above, 
discount of ten per cent is allowed to accredited agencies on orders for subscriptions 

and single copies. 
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 
General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 
Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., 
under the Act of March 3, 1879. 


Vol 48 MARCH 1947 No. 3 


Ed. Note. The Society of Motion Picture Engineers on Oct. 27, 1944, and on 
Mar. 2, 1945, through its representative, Paul J. Larsen. submitted recommenda- 
tions for allocations of frequencies for a national theater television service. The 
Federal Communications Commission on May 25, 1945, granted such allocations 
of frequencies for a national theater television service on an experimental, "parity 
of opportunity" basis with television broadcasting. 

On July 19, 1946, and Oct. 22, 1946, the FCC submitted a proposed revised fre- 
quency allocation for frequencies between 1000 and 13,000 megacycles, which elim- 
inated allocation of frequencies for the service of theater television. 

In view of this proposed revised frequency allocation, the SMPE, through its 
representative, Mr. Larsen, submitted opposition thereto on Feb. 4, 1947, which is 
presented here. 

Mr. Chairman, Members of the Commission: 

My name is Paul J. Larsen. I am a Radio Engineer, associated 
with the Johns Hopkins University and with the Bureau of Ordnance, 
U. S. Navy, in technical activities associated with the National de- 
fense of our country. I appear before the Commission today as the 
representative of the Society of Motion Picture Engineers, to present 
their opposition to the revised frequency allocations between 1000 
and 13,000 megacycles to nongovernment fixed and mobile services 
as proposed by the Commission in their Public Notice Nos. 95700 
and 99615, dated July 19, 1946, and October 22, 1946, respectively. 

The Society of Motion Picture Engineers, through my representa- 
tion, appeared before the Commission during the original hearings 
on recommendations for frequency allocations in this docket concern- 
ing request for frequency allocation requirements for a theater tele- 
vision service. The statement made by the Society of Motion Picture 
Engineers, presented on October 27, 1944, is on record as Federal 
Communications Commission Exhibit No. 431, and the statement 

* Presented before the Federal Communications Commission (Docket No. 6651) 
by Paul J. Larsen, SMPE representative, on Feb. 4, 1947. 


184 STATEMENT OF SMPE Vol 48, No. 3 

presented by the Society of Motion Picture Engineers on March 2, 
1945, is on record as Federal Communications Commission Exhibit 
No. 598. Copies of these exhibits as reprinted from the JOURNAL 
of the Society of Motion Picture Engineers, Vol 44, Nos. 2 and 4, 
are attached hereto as Appendix B for reference purposes. [Ex- 
hibits not reprinted here. Ed.] 

The Society of Motion Picture Engineers is composed of engineers 
from every group interested and active in furthering the engineering 
perfection of Motion Pictures as presented to the public. This art of 
Motion Pictures encompasses all engineering phases relating to visual 
and oral presentations, whether on film or by other means, such as 
television. The engineers of any industry are the ones whom that 
industry relies upon to guide them in determining the technological 
developments which the industry must prepare itself for, to improve 
or to enlarge the scope of their product to the public. 

The Motion Picture Industry of the United States of America is the 
largest of such industries in the world and one of the important indus- 
tries in America. The American Motion Picture Industry has a 
responsibility far surpassing that of any other industry, because of 
the fact that that industry presents to the public through visual and 
oral means a flow of entertainment and news which can guide the 
educational, economic, and moral trends of the population. Motion 
pictures are well known to be the major means of entertainment and 
instruction to the public at large. They are brought into urban and 
rural areas, and motion pictures are a great factor in the advancement 
in understanding, education, and entertainment. Motion pictures, 
as the words imply, are a presentation of any picture in motion, 
whether such presentation is carried on a film or transmitted through 
radio waves to the ultimate viewer, the visual presentation is still a 
motion picture. The Motion Picture Industry, therefore, has a 
direct interest in television, as television is another medium for pre- 
senting to the public motion pictures for the same purpose ; namely, 
advancement and understanding, education, and entertainment. 

The Federal Communications Commission, during the earlier 
hearings in this docket, recognized the Society of Motion Picture 
Engineers' request for frequency allocations for a theater television 
service by allotting for this service certain bands of frequencies for 
experimental purposes. This grant by the Federal Communications 
Commission opened the door for the Motion Picture Industry in the 
postwar period to initiate experimentation in the field of theater 


television on a parity basis with other services which were granted 
the same rights. The Commission did not allocate any of these fre- 
quencies to any specific service for three basic reasons, which are 
as follows: 

(1) Inadequate data were available regarding propagation characteristics in 
these frequencies to determine their usefulness for the specific services requesting 
these frequencies. 

(2) Very little information was available concerning equipment development 
in this frequency range, as most of the equipment developed was under military 
security, and the Federal Communications Commission therefore requested fur- 
ther information as to development and availability of equipment suitable for 
this frequency range. 

(5) The need by the respective Services for the frequency allocations requested 
should be proved after practical experience under actual operating conditions. 

The Society of Motion Picture Engineers has been extremely active 
in television, which covers broadly the two services in this field; 
namely, broadcasting to the public, and theater television. The 
Society of Motion Picture Engineers is a contributing sponsor to the 
Radio Technical Planning Board and has been active in all of the 
Radio Technical Planning Board's deliberations, having representa- 
tives on most of its panels. The two television committees of the 
Society of Motion Picture Engineers, the Television Engineering 
Committee and the Television Projection Practice Committee, have 
been active in all engineering phases of the television art. 

The membership of these committees consists of most of the out- 
standing television engineers of the Industry, as well as members 
from producers and exhibiting companies of the Motion Picture 
Industry. An alphabetical list of the membership of these commit- 
tees and an alphabetical list of the companies whom these members 
represent is attached as Appendix A . The engineering deliberations 
of the Television Projection Practice Committee of the Society of 
Motion Picture Engineers have been reported to all of the technical 
television committees of The Institute of Radio Engineers, the Radio 
Manufacturers Association, and the Radio Technical Planning Board. 
Many of the technical decisions made by these other engineering bod- 
ies have been based Upon the work conducted by the Television Com- 
mittees of the Society of Motion Picture Engineers. Reference to 
this engineering activity by the Society of Motion Picture Engineers 
Television Committees has been cited from time to time in hearings 
before the Federal Communications Commission in this docket and 
also in the present hearing on "Color Television" (Docket No. 7896). 



Vol 48, No. 3 


C U_ ? 





March 1947 



The allocation of frequencies by the Federal Communications Com- 
mission between 1000 and 13,000 megacycles to specific nongovern- 
ment fixed and mobile services, as proposed in Public Notice No. 
99615, removes for experimental purposes all frequencies up to 13,000 
megacycles. For purposes of comparing this proposed frequency 
allocation with (1) the allocation granted by the Federal Communica- 
tions Commission in their report, dated May 25, 1945 (Public Notice 


1000 to 5000 Me 

5000 to 13,000 Me 

1000 to 13,000 Me 



































Between 1000 to 13,000 Megacycles 


Total Band 



Aviation, Navigation, 


Navigation Aids 
Not Assigned 

Television Relay 

Television STL 

Television Pickup 
Mobile General 
Fixed Circuits 
Common Carrier 


The "Nongovernmental Experimental" frequency allocation above was made available to 
all nongovernmental services for experimental purposes until such time that a showing of need 
for definite assignment of specific frequencies in bands of frequencies above 1000 megacycles can 
be established. Such need to be based upon (/) practical experience under actual operating 
conditions; (2) further data regarding propagation characteristics; and (3) further information 
concerning equipment development. 

8.0 2.0 

8.0 0.66 


28.75 3900 48.72 



No. 82387), and (2) the original requests made by the different serv- 
ices and the Radio Technical Planning Board during the original hear- 
ings in this docket, the following tables are submitted : 

Table 1 Original Allocations May 25, 1945 (Public Notice No. 82387). 
Table 2 Original Requests by different nongovernment services. 
Table 3 Original Requests classified as to basic type of facility. 
Table 4 Original Requests by Society of Motion Picture Engineers and Com- 
mon Carriers and Allocations for Experimentation. 
Table 5 Proposed Allocations classified as to basic type of facility. 



Vol 48, No. 3 


K) O 


o "- 


X Q. 



O ^ 

O > 


O uj 
Z h- 


cr ! S 

Z S .2 

o o -g 

2 S J 
o >s is 










Between 1000 to 13,000 Megacycles 


Item Panel Service 

1 8 Fixed Circuits 

Remote Control 

2 8 Fixed Circuits 

Short Toll 

3 4 Broadcast Pickup 

4 4 Broadcast S.T.L. 

5 6 Television Relay 

6 13 Police 

7 13 Forestry 

8 13 Forestry and Conserva- 


9 13 Railroad Relay, etc. 

10 13 General Mobile Bus 

11 13 General Mobile Truck 

12 8 Rural Telephone 

13 9 Relay-Portable and 


14 9 Relay-General 

15 9 Relay-Intercity Tele- 


16 9 Relay-Exp. Intercity 


17 9 Relay-Exp. Nonexclu- 


18 9 SMPE 

19 9 AT&T 

20 9 Western Union 

21 9 Raytheon 

Total Requests 

1000 to 
5000 Me 



9.6 b 
400 6 




8.50 6 

100 C 

800 fc 
413. 6 6 
392 & 


5000 to 
13,000 Me 





2650 d 

465. Q d 
262 d 



1000 to 

13,000 Me 




15. V 












Request Item 3 included in request of Item 13. 

b Requests Items 4, 5, 18, 19, 20, and 21 included in request of Item 14. 
c Request for 100 megacycles in Item 18 included in request of Item 15. 
d Requests Items 4, 18, 19, 20, and 21 included in request of Item 17. 
f- Request for 400 megacycles in Jtem 18 included in request of Item 17. 

f Requests Items 3, 4, 5, 18, 19, 20, and 21, totaling 5028.8 megacycles, included in Requests 
Items 13, 14, 15, 16, and. .77 totaling 4100 megacycles. 



Vol 48, No. 3 



iO 00 





o a 

^ 6 

y co 
g t 
< R 


x cr Q- 

z z 

t-= g o 

O to to 

o > > 

Z _) _j 

O uj uj 

Z h- I- 





March 1947 



These tables list the requests, original allocations, and proposed allo- 
cations by frequencies for the different services, and the percentage 
that these frequency or allocation requests represents to the total 
frequency bandwidth. 

To assist in further study of the proposed allocations with those 
formerly granted on an experimental basis, three charts are attached 
hereto as follows : 

Plate 1. Frequency Service Allocations, Frequency Band 400 to 1000 

Plate 2. Frequency Service Allocations, Frequency Band 1000 to 5000 mega- 

Plate 3. Frequency Service Allocations, Frequency Band 5000 to 13,000 
megacycles. . 


99615, DATED OCTOBER 22, 1946 

Between 1000 to 13,000 Megacycles 

1000 to 
5000 Me 

5000 to 
13,000 Me 

1000 to 
13,000 Me 









Total Band 








Broadcast STL 








Broadcast Pickup 


Mobile General 








Fixed Circuits 









Common Carrier 







Includes request of SMPE, on basis that request of SMPE for frequencies for a Theater 
Television Service is considered Common Carrier because of its private nature not open to public 

It will be noted from the above five tables and the attached plates 
that all nongovernmental experimental bandwidths according to the 
Federal Communications Commission's proposal of October 22, 1946 
(Public Notice No. 99615), have been allocated to specific services, 
leaving no bands available for experimentation for new services. 

The Society of Motion Picture Engineers, representing all of the 
engineers of the Motion Picture Industry, strongly oppose this 



Vol 48, No. 3 

proposal by the Federal Communications Commission, as the alloca- 
tions are not in the best public interest, and are contrary to the 
general principles the Commission employed in making the original 
allocations; and further, to the best knowledge of the Society of 
Motion Picture Engineers, no need for this allocation at this time has 
been shown by any of the services to whom the Commission is allocat- 
ing these frequencies. Referring to Table 3, it will be noted that the 
service "Mobile General" originally requested only 25 megacycles 



NOTICE 82387 

Between 1000 to 13,000 Megacycles 

1000 to 
5000 Me 





SMPE Request 
W.U. Request 
Raytheon Request 
AT&T Request 
RTPB Recommendation 
FCC Allocation 

5000 to 
13,000 Me 

1000 to 
13,000 Me 

















1000 6 


1800 6 






3900 a 




600 15 

413.6 10.34 

372 9.3 

800 20.0 

1150 28.75 

1150 a 28.75 

Experimental operation with intra- and intercity relay of theater television, including multi- 
ple address purposes permitted in following bands: 1325-13751, 1750-2100, 2450-2700, 3900- 
4400 2 , 5650-7050, 10,500-13,000, 16,000-18,000, and 26,000-30,000 megacycles. 
1 Revised November 19, 1945, Public Notice No. 86131 to band 1375-1425. 
* Revised November 19, 1945, Public Notice No. 86131 to bands 3700-4000 and 420-4400. 
b Original request by AT&T was ? channels ? wide in band 11,500-12,500 megacycles. 

for experimental purposes in the band from 1000 to 13,000 mega- 
cycles, whereas in the proposed allocation the Federal Communica- 
tions Commission is allocating 925 megacycles to that service in this 
same band. The service "Fixed Circuits" originally requested only 
910 megacycles in the band of 1000 to 13,000 megacycles; whereas 
the proposal allocates 1525 megacycles in this band to this service. 
The services "Television, Studio Transmitter Links (STL) and 
Pickup" orginally requested only 125.6 megacycles in the band of 
1000 to 13,000 megacycles; whereas the proposal allocates 880 
megacycles in this band for these services. 

From Tables 2 and 3 it will be noted that all nongovernment 
services requested a total of 5035 megacycles in the band between 
1000 to 13,000 megacycles. This request was determined after joint 

March 1947 



conference between Panels 2, 4, 5, 6, and 9 of the Radio Technical 
Planning Board on November 1, 1944, during the original hearings 
before the Commission in this docket. The Radio Technical Plan- 
ning Board Panel 2 submitted recommendation for 5100 megacycles 




Between 1000 to 13,000 Megacycles 

1000 to 
5000 Me 




5000 to 
13,000 Me 


1000 to 

13,000 Me 





4000 100 

8000 100 

12,000 100 


















Total Band 



Aviation Na vigat ion 

Navigation Aids 
Not assigned 5650 

5850 me 

Television Relay 
Television STL 
Television Pickup 
Mobile General 
Fixed Circuits 
Common Carrier 
Nongovt. Experimental 

Mobile except Television Pickup which denotes all types of mobile operations except for tele- 
vision pickup . . . etc. 

& Fixed Circuits except Common Carrier and Television STL which includes fixed control cir- 
cuits (including those controlling fixed public service circuits) and radio-relay systems not open 
to public correspondence which are operated by and for the sole use of agencies exclusively in 
the safety and emergency services such as police, aviation, railroad, petroleum, and others. 

c Common Carrier Fixed Circuits which include not only those communications common car- 
riers furnishing message service to the general public, but also those rendering communications 
service to a limited class of users. 

d Television Pickups and Television Studio Transmitter Links (STL) which are radio facilities 
where wire service is not economically practicable and will be licensed only to licensees of television 
broadcast stations and to common carriers. 



275 d 






725 b 




1,525 6 


500 C 


1500 C 


2,000 C 


(Table 4) and the Commission in their report dated May 25, 1945 
(Public Notice No. 82387), allocated 5050 megacycles on an experi- 
mental basis for "nongovernment fixed and mobile service" (see Table 
4 and Plates 2 and 3) in the band of 1000 to 13,000 megacycles. 

194 STATEMENT OF SMPE Vol 48, No. 3 

From Table 3 it will be noted that, after deducting 1060.6 mega- 
cycles for other services, 3974.4 megacycles of the 5035 megacycles 
requested in Table 2, based upon classification in Public Notice No. 
99615, remains for "Common Carrier" service which includes the 
Society's request for Theater Television. From this total 400 mega- 
cycles should be deducted for the service "Television Relay" requested 
by Panel 6 (Item 5, Table 2), for Television STL and Pickup, leaving 
3574.4 megacycles for the Society of Motion Picture Engineers, 
Western Union, Raytheon, and American Telephone and Telegraph 
requests totaling 4513.2 megacycles (Table 4 and Plates 2 and 3). 
On a percentage basis based upon the original requests of these or- 
ganizations, frequency allocations to these organizations on a parity 
basis if public need can be proved would be as follows : 

Allocation Based 

Original on Only 3574.4 

Requests, Megacycles 

Organization Me. Per Cent Being Available, Me. 



Total 4513.2 100 3574.4 

The proposed allocation of only 2000 megacycles to the service 
"Common Carrier" in the band of 1000 to 13,000 megacycles does not 
seem adequate on this basis of computation, and seems to limit this 
service in view of proposed excessive proposed allocations to other 
services beyond their original requests. 

The opposition by the Society of Motion Picture Engineers to the 
proposed allocation is mainly based upon their not having knowledge 
as to the type of radio facility the Federal Communications Commis- 
sion considers theater television. In the original request by the So- 
ciety of Motion Picture Engineers, Federal Communications Com- 
mission Exhibit 431, the Society directed the attention of the Federal 
Communications Commission to the fact that theater television in- 
vokes communications of a private nature, and therefore such service 
should be accordingly classified to differentiate it from standard tele- 
vision broadcasting. It is the Society's opinion that theater television 
should be classified under the following two basic types of facilities 
referred to in Public Notice No. 99615, namely: 


(1) Common Carrier Fixed Circuit, and 

(2) Fixed Circuits except Common Carrier and Television Studio Transmitter 


Theater television is a communication which renders a service to a 
limited class of users and therefore comes under the definition of a 
"Common Carrier". The definition that the Commission has made 
for the second class of service, "Fixed Circuits except Common Carrier 
and Television Studio Transmitter Links", namely, that "radio-relay 
systems not open to public correspondence which are operated by and 
for the sole use of agencies operating exclusively in the safety and 
emergency services, such as police, aviation, railway, petroleum, and 
others", is excepted to, in view of the proposed allocation. The Society 
objects to the proposed allocation of 1525 megacycles to the service 
"Fixed Circuits" in the band 1000 to 13,000 megacycles, in view of this 
service having only requested 910 megacycles, and further because of 
the fact that, to the best knowledge of the Society of Motion Picture 
Engineers, no need for any definite assignment to this service for even 
their original request exists at this time. 

The Society of Motion Picture Engineers also takes exception to 
the statement in Public Notice No. 99615 that, "Television Pickup 
and Television STL stations will be licensed only to licensees of television 
broadcast stations and to common carriers", unless the Commission 
definitely classifies theater television service as a "Common Carrier" 

The Society of Motion Picture Engineers also strenuously opposes 
the following statement by the Commission in Public Notice No. 

". . .since the Commission believes that there is not sufficient spectrum space 
available in the nongovernment fixed and mobile bands between 1000 to 13,000 
megacycles to accommodate an inter-city television relay service and at the 
same time provide adequate space for other nongovernment fixed and mobile 
services with a requirement for frequency in this range, no provision for such a 
service has been incorporated in this proposal. . . " 

This opposition is made by the Society of Motion Picture Engineers 
as the statement would imply that no intercity television relay service 
of any kind for either television broadcasting or theater television can 
be established in any frequency band between 1000 to 13,000 mega- 
cycles. Does this statement imply that no television relay networks 
for coast-to-coast programming for either television broadcasting pur- 
poses or theater television purposes can be established, and that such 

196 STATEMENT OF SMPE Vol 48, No. 3 

programming on a national scale must be limited to coaxial cable or 
wave guide circuits which are technically limited and controlled by a 
single organization? If such is the case, the proposed allocation for 
the service "Common Carrier" of 2000 megacycles does not seem to 
be supported by requirements of that service. 

The Commission also states in their proposal, "that allocations for 
Television Pickup and Television STL services are radio facilities . . . 
which are used where wire service is not economically practicable." Al- 
though there are no basic radio services, except ship-to-shore, automo- 
bile and airplane service which cannot be accomplished by other 
means than radio, radio has gained its position in the field of communi- 
cations because it has given more immediate and better service at 
lower cost. Existing services have been encouraged, guided, and pro- 
tected during their development and commercialization. Some of 
these services might never have existed had allocations and legisla- 
tion blocked the road to their development and success. The new 
services, including theater television, should be encouraged and pro- 
tected during their development and ultimate commercialization; and, 
therefore, no limitations during these periods should be placed upon 

The Society of Motion Picture Engineers has assumed that the 
Commission's proposed allocation is undoubtedly made at this time 
on the basis that multiple use of channels may better meet such con- 
gestion as may arise in the future in this band of 1000 to 13,000 mega- 
cycles. This multiple use of channels may be correct thinking today 
if television, whether for broadcasting or for theater use, is only to be 
transmitted a few hours a day. However, it can be assumed that, if 
television for broadcasting and for theater use is to be commercialized 
to the same extent as present sound broadcasting, such service must 
be available on a twenty-four hour basis to meet a National Service. 
Theater television to evolve into an economically sound business 
must be very extensive, necessitating nation-wide distribution. 
Sound broadcasting would never have been an economically sound 
business unless it had this extensive nation-wide service. 

Motion pictures using films would never have been an economically 
sound business unless it had its nation-wide distribution to the thea- 
ters. Television Broadcasting will never be an economically sound 
business unless it has nation-wide distribution. Theater television will 
undoubtedly require circuits which will be special in nature and much 
- time will be lost in gaining co-ordination between a common carrier, 


who has other services to supply, and a client such as the Motion Pic- 
ture Industry, that cannot make a profit unless it can gain wide utili- 
zation. Allocating the frequencies at this time to specific services, 
before such services have shown an actual need, seems in error and 
prejudicial to the best interest of the American people. Technological 
progress should not be stifled and this generation should not be de- 
prived of a service such as theater television or television broadcasting 
to which they are entitled. 

The Motion Picture Industry has been very active in the field of 
television. Many companies have established separate divisions to 
delve into the technical problems, and other divisions to assist tele- 
vision broadcasters in the employment of film for television use. 
The Commission may question whether or not the Motion Picture 
Industry, up to this time, has taken advantage of the experimenta- 
tion offered to them in the radio spectrum for this field. It is true 
that no member of the Motion Picture Industry has applied for li- 
censes to experiment with transmission of television programs from 
point to point, or with intermediate links. The Industry, however, 
has been active in engineering considerations of the problems that 
confront them. 

During the past year, industrial readjustments have been necessary 
which have affected not only the Motion Picture Industry but every 
other industry which has been before the Commission. Equipment 
developments by the electronic manufacturers have not progressed 
sufficiently to provide microwave relaying for this service. The ter- 
minating equipment at the theater has been under development for 
many years, by members of the Motion Picture Industry and by radio 
manufacturers; and until such terminating equipment is available 
embodying all of the technical requirements and capable of producing 
the brightness necessary to present a television picture on a large 
screen in a Motion Picture Theater, no need for the radio facilities 
arises. It would be surprising, indeed, if the Motion Picture In- 
dustry were able, in this short time, to tie together with terminating 
equipment all of the practical equipment for the accomplishment of 
a microwave relaying television service, when the simpler and less 
exacting service of television broadcasting is still in its earlier stages of 
development and commercialization. 

Motion pictures are this nation's "number one" form of entertain- 
ment and relaxation. It is a service important to the happiness, the 
well-being, and the health of our people. It should not be deprived 

198 STATEMENT OF SMPE Vol 48, No. 3 

of the opportunity of improving that service to the people through the 
greater use of technical developments in electronics and the peacetime 
utilization of developments and applications still to be conceived. 
The public is concerned with what goes into the electronic input 
equipment and what comes out at the receiver, whether that be tele- 
vision broadcasting or theater television. This is a field in which 
the Motion Picture Industry has spent millions and as of this date is 
spending more millions in a sincere effort to gain the desired form of 
visual expression through the avenues of television. 

One of the general principles that the Commission followed in mak- 
ing the original allocations was its concern over the total number of 
people who would receive benefits from the particular service, and 
where other factors were equal, the Commission attempted to meet 
the requests of those services which proposed to render benefits to 
large groups of the population, rather than of those services which aid 
relatively small groups. This principle is one that the Society of 
Motion Picture Engineers stressed at its original presentation/ It 
will be found that only the telephone and sound broadcasting serve 
the equivalent of more than the 90 million people who attend the 
motion picture theaters every week. On this fact alone, theater tele- 
vision should have the same parity of right for frequency allocations 
as television broadcasting. 

Another principle that the Commission followed in the original 
allocations was to determine whether such newer services met a sub- 
stantial public need; and if frequencies are granted, that the service 
could be established on a practical working basis. The Society of 
Motion Picture Engineers concurs in this principle, and for that rea- 
son opposes the allocation or "freezing" of frequencies in the band 
1000 to 13,000 megacycles to any service at this time, as it does not 
believe that any of the services to date have proved that they could 
be established on a practicable working basis and that these services 
meet a public need. 

Another principle that the Commission followed in considering 
the proper place in the spectrum for the services in question was 
the inadequate information on radio-wave propagation characteris- 
tics of the various portions of the spectrum. The Society of Motion 
Picture Engineers is of the opinion that information as to the propaga- 
tion characteristics of frequencies within the band of 1000 to 13,000 
megacycles is still inadequate to determine definitely the proper place 
in the spectrum for the respective services. 


The frequency band under consideration, 1000 to 13,000 megacy- 
cles, is 12,000 megacycles wide, which is 12 times larger than the 
O-to-1000 megacycle band, which prior to World War II carried all 
radio transmissions of every description throughout the world. The 
frequency range under consideration is almost entirely line-of -sight 
and transmission, therefore, can be very directional, thus making it 
possible for many services to use the same frequencies within the same 
line-of -sight areas and to repeat over and over again the use at these 
same frequencies in areas beyond line-of -sight interference. 

The inadequate experience under actual operating conditions and 
limited equipment development in this band of 1000 to 13,000 mega- 
cycles to date should leave the door open for continued experimenta- 
tion to all services and not limited to a few. Freezing of this band at 
this time to the services indicated in the proposal will discourage 
and/or stop research or development which potentially can make 
this band of much greater use and value. Retaining this band for 
experimental purposes may prove that the bandwidth is adequate for 
all services without congestion when considering the propagation 
characteristics and directional capability of transmission at these 

The Society of Motion Picture Engineers respectfully submits to 
the Federal Communications Commission the following recommen- 
dations : 

(1) Classify, under a basic radio facility, a theater television service which in- 
volves communications of a private nature. 

(2) Retain present nongovernment fixed and mobile experimental bands in 
the frequency spectrum between 1000 and 13,000 megacycles on same basis of ex- 
perimental authorization to all services as allocated in the "Report of Allocations 
from 25,000 kilocycles to 30 million kilocycles", dated May 25, 1945 (Public 
Notice No. 82387), and as modified by Public Notice No. 86131, dated November 
19, 1945. 

The Society of Motion Picture Engineers, on behalf of the Engi- 
neers of the Motion Picture Industry, respectfully requests the Fed- 
eral Communications Commission to grant the above recommenda- 
tions so as to permit the American Motion Picture Industry to experi- 
ment for the purpose of initiating theater television and to assist it to 
maintain its world leadership in the visual and oral entertainment 



Vol 48, No. 3 

Appendix A 










L. W. Davee 













E. I. du Pont de Nemours & Co., Ii 
Johns Hopkins Univ. & U. S. Navy 

RCA Victor Division 

Paramount Pictures, Inc. 

RKO Television Corp. 

Bell Telephone Labs., Inc. 

International Projector Corp. 

RCA, Camden, N. J. 

RCA, Camden, N. J. 

RCA Victor Division, New York 

Pathe News, Inc. 

National Carbon Co. 

Fox Movietone News, Inc. 

Warner Bros. Pictures, Inc. 

General Electric Co. 


General Electric Co. 

Century Projector Corp. 

Hazeltine Electronic Corp. 

J. & D. Eberson, Architects 

RCA Laboratories, Inc. 

Columbia Broadcasting Co. 

A. B. DuMont Labs., Inc. 

National Theatre Supply Co. 

General Electric Co. 

Television Productions, Inc. 

Sperry Gyroscope Co., Inc. 

International Projector Corp. 

Columbia Broadcasting Co. 


A. B. DuMont Labs., Inc. 

National Broadcasting Co. 

Bell Telephone Labs., Inc. 

International Projector Corp. 

Bell Telephone Labs., Inc. 

RKO Service Corp. 

Eastman Kodak Co. 

Loews, Inc. 

Bell Telephone Labs., Inc. 


Eastman Kodak Co. 



C. M 












































. . 















March 1947 
















M Member 

A Alternate 

X Consultant 

Y Ex-Officio Member 


Projectionist, Local 306 
Farnsworth Telev. & Radio Corp. 
Warner Bros. Pictures, Inc. 
Research Council, A.M.P.A.S. 
General Precision Labs., Inc. 
National Carbon Co. 
Don-Lee Broadcasting Co. 
SMPE (Engineering Vice-Pres.) 
Bell Telephone Labs., Inc. 
Metro-Goldwyn Mayer, Inc. 
State of Conn., Dept. of Police 
SMPE (Engineering Secretary) 
Loews, Inc. 

Mutual Broadcasting Co. 
Paramount Pictures, Inc. 
Bausch & Lomb Optical Co. 
Television Production, Inc. 
National Carbon Co. 
Scophony, Inc. 
Paramount Pictures, Inc. 
Eastman Kodak Co. 
Research Council, A.M.P.A.S. 
B. Schlanger, Architect 
Natl. Broadcasting Co. 
SMPE (Executive Secretary) 
Twentieth Century-Fox Film Corp. 
Rauland Corp. 
Columbia Broadcasting Co. 
I.A.T.S.E., Cleveland, Ohio 
Eastman Kodak Co. 
General Electric Co. 























Ansco Division, General Aniline and Film Corp. 

Bausch and Lomb Optical Co. 

Bell Telephone Laboratories, Inc. 

Century Projector Corp. 

Columbia Broadcasting Co. 

Don-Lee Broadcasting Co. 

A. B. DuMont Laboratories, Inc. 

E. I. du Pont de Nemours & Co., Inc. 


Eastman Kodak Co. 

J. & D. Eberson Architects 

Farnsworth Telev. & Radio Corp. 

General Electric Co. 

General Precision Labs., Inc. 

Alfred N. Goldsmith, Consultant 

Hazeltine Electronics Corp. 

International Projector Corp. 

I.A.T.S.E. (Cleveland) 

Johns Hopkins University 

H. E. Kallman, Consultant 

Loews, Inc. 

Metro-Gold wyn Mayer, Inc. 

Mutual Broadcasting Co. 

National Broadcasting Co. 

National Carbon Co. 

National Theatre Supply Co. 

Paramount Pictures, Inc. 

Pathe News, Inc. 

Projectionist, Local 306 

Radio Corporation of America 

RCA Laboratories, Inc. 

Rauland Corp. 

Research Council, Academy of Motion Picture Arts and Sciences 

RKO Service Corp. 

RKO Television Corp. 

B. Schlanger, Architect 

Scophony, Inc. 

Sperry Gyroscope Co., Inc. 

State of Conn., Dept. of Police 

Television Productions, Inc. 

Twentieth Century-Fox Film Corp. 

Warner Bros. Pictures, Inc. 


JANUARY 1, 1946, TO DECEMBER 31, 1946 


Increased interest in the work of the Society is shown by the large 
increase in membership during the year. The net increase for the 
year for all grades is 466, which is the largest increase in the history 
of the Society. Total membership now stands at 2432, which in- 
cludes 6 Honorary, 64 Sustaining, 154 Fellow, 561 Active, 1588 As- 
sociate, and 59 Student Members. 


Through the efforts of the President, D. E. Hyndman, the financial 
support provided by Sustaining Members has been more than 
doubled. From a total of $8087.50 received from this source in 1945, 
the receipts rose to $20,250 in 1946. This increase is the result of 
both larger subscriptions from previous Sustaining Members and a 
considerable increase in the number of such members. Notable 
among the new Sustaining Members is the Motion Picture Associa- 
tion of America. 

The Society membership dues have also increased income in 1946 
by about $2750. However, rising costs of publishing the JOURNAL 
and increased expense in maintaining the larger office staff required 
to handle expanded membership and committee activities have more 
than used up all this increased .income, so it has been necessary to 
raise the annual dues of Associate and Student Members to $10 and 
$5, respectively. Dues of Active Members and Fellows were not in- 
creased, since it was felt by the Board of Governors that the dues 
of these grades had been increased proportionately more than the 
other grades at the last change. Sales of test films continued to be 
considerable, although not so great as in the previous year. A settle- 
ment was made with the supplier, J. A. Maurer, Inc., whereby the 
special equipment used in making these test films becomes the 

* Submitted Feb. 4, 1947. 




property of the Society. Total income from all sources exceeded the 
total expenses by over $3000. 


An active Midwest Section has been organized in Chicago, after a 
period of three years in which the Section was discontinued. Under 
the leadership of A. Shapiro, Chairman, and R. E. Lewis, Secretary- 
Treasurer, the Section has held nine meetings since its organization 

Membership Growth of the Society. 

in March. Meetings are ordinarily held in the rooms of the Western 
Society of Engineers, and frequently are attended by a capacity audi- 
ence. The Section is now actively working on arrangements for the 
Spring Convention to be held in Chicago, April 21-25, 1947. 


In order to handle the very large increase in Society business, it has 
been necessary to increase the General Office staff as follows : Boyce 
Nemec has been appointed Engineering Secretary to assist the various 
engineering committees, and provide technical advice on questions 
arising in office correspondence. Miss Silvya Roth has been engaged 


for general secretarial work and stenotype service. Mrs. Winifred 
Carriere has been engaged as part-time editorial assistant. These 
additions to the staff have helped, but have not entirely relieved the 
overload of work at the General Office. The office space, previously 
crowded, is now seriously overcrowded, but so far it has not been 
possible to obtain larger quarters. The many details involved in the 
sale of test films and American Standards have added to the work 
which had already increased owing to larger membership. Every ef- 
fort is being made to overcome the handicap of insufficient space and 
secretarial assistance but, in the meantime, members are asked to be 
patient when the JOURNAL does not arrive on time or correspondence 
is delayed. 


The past year has been one of unusual activity for most of the en- 
gineering committees but particularly for the Standards Committee. 
Under the chairmanship of F. T. Bowditch, the Standards Committee 
has had under consideration 22 standards referred to it for revision 
by the American Standards Association Sectional Committee on Mo- 
tion Pictures, Z22. Among these a number, such as the standards 
on 8- and 16-mm sprockets, were completely revised so that the data 
could be presented in more useful form. New standards for 8- and 
16-mm film splices have been proposed and published. A considerable 
amount of work was done on a revision of the pitch diameter of 35- 
mm sprockets. Edge numbering, 16-mm apertures, cutting and per- 
forating standards, and photographic density have also received con- 
siderable attention. Recommended revisions for five standards have 
been referred to the Z22 Committee. A report of this committee is 
given on page 110 of the August 1946 issue of the JOURNAL. 

The Committee on Television Projection Practice under the chair- 
manship of P. J. Larsen was organized in 1945 for the purpose of mak- 
ing recommendations on the design, construction, installation, main- 
tenance, and operation of equipment for projection of television pic- 
tures in theaters. Three Task Groups were formed to gather infor- 
mation on (a) engineering details of television projection equipment; 
(b) dimensions and other data on theater auditoriums, stages, and 
projection booths; (c) projection television picture quality; and a 
fourth is planned to work on distribution and commercial problems. 
Preliminary reports of the first three of these groups have been of 
considerable use to the Radio Technical Planning Board, and the IRE 


and RMA Television Committees, and will be published in an early 
issue of the JOURNAL. 

The Committee on 16-Mm and 8-Mm Motion Pictures is working 
on a comprehensive report which is expected to take the form of 
recommendations on the use of 16-mm motion picture equipment in 
educational and industrial fields. This will replace the "Report of 
the Committee on Nontheatrical Equipment", issued in 1941, the 
distribution of which has reached over 1000 copies. 

The Committee on Studio Lighting issued a report giving consider- 
able data on the light intensity and distribution for seven types of 
lighting units commonly used in motion picture studios. This report, 
published in the August 1946 issue of the JOURNAL, also gives data on 
key-light levels for black-and-white and for color cinematography. 


The Committee on Preservation of Film, under the chairmanship 
of J. G. Bradley, is considering the expanding problem of film preser- 
vation caused by the vast quantities of film exposed for military pur- 
poses during the war, estimated at possibly 300,000 reels. Proposals 
are being considered for revised-recommendations on the construction 
of film vaults. Also under discussion are storage containers and 
cores, more permanent film base materials, and processing technique 
for permanent record films. 


Under the chairmanship of Henry Anderson, the Committee on 
Theater Engineering, Construction, and Operation is preparing a 
comprehensive report on the selection, installation, and care of car- 
pets. Also in preparation are reports on electric heaters for projec- 
tion booths, and gas or gasoline generators for emergency theater 


An important development in 1946 was the establishment of a 
Joint Committee on Test Films, with the following members from 
the Society and from the Research Council of the Academy of Motion 
Picture Arts and Sciences: Merle Chamberlin and L. T. Goldsmith 
representing the Research Council, and J. G. Frayne and J. A. Maurer 
representing the Society. This committee is to make recommenda- 
tions on the types of test films needed and the organization best suited 


production of particular films. By avoiding duplication of effort, 
is anticipated that both the number and quality of test films can 
improved. Working with this committee, the SMPE Projection 
lice Committee has brought out a new 35-Mm Picture Projec- 
ions Test Film which should be of great value to all those interested 
keeping picture projection equipment operating at highest effi- 
icy. The film consists of four parts designed to indicate and meas- 
ure (a) size of projector aperture and screen masking; (b) travel 
ghost; (c) picture unsteadiness; and (d) lens distortion. 

As rapidly as possible, specifications will be drawn up for test films 
in use but not previously standardized so that these can be submitted 
to the ASA Z22 Committee for consideration as American Standards. 
All test films will be distributed by both the Society and the Research 


Progress Medal. E. A. Williford, Chairman of the Progress Medal 
Award Committee, reported that the committee had no nominations 
to propose for 1946, so no award was made. 

Honorary Membership. On the recommendation of the Honorary 
Membership Committee, the Board of Governors voted to place the 
names of Theodore W. Case, Edward B. Craft, and Samuel L. Warner 
on the Honor Roll of the Society. This action was approved by 
unanimous vote of qualified members present at a business session of 
the Society in Hollywood on Oct. 21, 1946. It was also provided that 
the names of Honorary Members should be published in the JOURNAL 
with the listing of Society committees whenever the latter are pub- 

Fellow Award. Following the recommendation of the Fellow 
Award Committee the following Active Members were elevated to the 
grade of Fellow: R. B. Austrian, E. A. Bertram, J. W. Boyle, T. T. 
Moultdn, W. H. Offenhauser, Jr., L. T. Sachtleben, and A. Shapiro. 

Citations. In commemoration of the 50th anniversary of the first 
commercial exhibition of motion pictures, a citation was voted for 
Thomas Armat. A Scroll of Achievement bearing the citation was 
accepted at the Dinner-Dance of the May convention by Lt. Brooke 
Armat on behalf of his father. 

A citation and Scroll of Achievement were also presented at the 
same convention to the Warner Brothers for their achievements in 
commercializing sound motion pictures. The award was accepted 
by Maj. Albert Warner. 


At the Hollywood convention, additional citations were made to 
the following organizations which contributed to the first commercial 
use of talking motion pictures and the technical progress of the indus- 
try during the last twenty years : 

Bell Telephone Laboratories 
Lee de Forest 
General Electric Company 
Metro-Goldwyn-Mayer Studio 
Radio Corporation of America 
Twentieth Century-Fox Film Corporation 
Western Electric Company 
Westinghouse Electric Corporation 

SMPE Samuel L. Warner Memorial Award. The Board of Gov* 
ernors accepted the generous offer of Warner Brothers Pictures, Inc., 
to establish a fund for an annual award to be given to an individual 
contributing to engineering or technical improvement of the motion 
picture industry. The conditions upon which the award is made will 
be determined by the Society. The following committee has been ap- 
pointed to make recommendations for the conditions and the form of 
award: C. R. Keith, Chairman, T. T. Moulton, and Nathan Levin- 


In accordance with a recent amendment to Article IV of the Con- 
stitution, the terms of office of the Secretary and of the Treasurer 
are now two years each. In order to comply with a provision of the 
same article, that election to these two offices should be held in alter- 
nate years, the Board of Governors ruled that the term of office of the 
Treasurer elected in 1946 should be one year, and thereafter two years. 

Numerous revisions were made in the Administrative Practices to 
bring them up to date. Since the Administrative Practices are 
simply a collection of resolutions by the Board of Governors defining 
duties of officers in more detail than in the By-Laws, these changes 
were not submitted to a vote of the Society. One of the more im- 
portant of these changes is the delegation to the Past-President of 
the duty of soliciting dues from Sustaining Members. 

The procedure for formally adopting standards has been revised 
in an effort to encourage discussion of proposed standards and also 
to expedite consideration. The principal changes call for publication 



of the proposed standard, with a digest of the preliminary committee 
discussion, before final voting by the Standards Committee. 


By unanimous vote, members of the Society at the Hollywood con- 
vention adopted By-Law XIII, which provides for Student Chapters 
in colleges, universities, or technical institutions. A Student Chapter 

Staff of SMPE General Office, left, standing, MARGARET C. KELLY, 
Financial Assistant; HELEN KRAWCHUK, Secretary; SILVYA ROTH, Techni- 
cal Secretary; BEATRICE MELICAN, Secretary; seated, left, HARRY SMITH, 
JR., Executive Secretary; and BOYCE NEMEC, Engineering Secretary. 

has been proposed at the University of Southern California and the 
Board of Governors authorized the expenditure of necessary organi- 
zation expenses. The President appointed the following committee 
to give further study to problems involved in the establishment of 
Student Chapters: L. L. Ryder, Chairman, M. R. Boyer, C. R. 
Daily, A. C. Hardy, C. R. Keith, and R. E. Lewis. 


A ten-year index of the JOURNAL from 1936 through 1945 is being 
prepared. Owing to the pressure of work at the General Office it is 


not possible to say when the 1936-'45 index will be distributed, but 
every effort is being made to complete it in 1947. Hereafter it is 
planned to prepare indices every five years. 

During the year, a revised membership list was issued. Revision 
of the list was impractical during the war because of many frequent 
changes of address, particularly by those in the Armed Services, but 
now that most members are in relatively permanent locations, it is 
planned to issue a revised membership at more frequent intervals. 

A special loose-leaf binder has been made available to hold Ameri- 
can Motion Picture Standards. This has been furnished to members 
at cost, together with the provision that each purchaser is notified 
whenever new motion picture standards are available. 

A comprehensive list of educational institutions giving courses on 
subjects relating to motion pictures has been prepared by the Com- 
mittee on Motion Picture Instruction under the chairmanship of 
J. G. Frayne. This report, published in the August 1946 issue of the 
JOURNAL, also lists the courses, semester hours, and credits for each 
subject at each institution. 

Respectfully submitted, 





Summary. A new series of highly corrected anastigmatic lenses with an aper- 
ture ratio off/2.3 is offered for 16-mm motion picture cameras. Surfaces are given 
antireflection coatings. A new type of mount guarantees centration. 

Sixteen-millimeter motion picture equipment was designed pri- 
marily for the amateur with the inevitable result that cost was one 
of the principal guiding considerations. This involved both the opti- 
cal systems as well as the mechanical design. The possibilities in- 
herent in 16-mm motion pictures for more serious work engaged the 
attention of the camera makers before it received adequate attention 
from the projector designers, and yet it seems as if even the camera 
makers have not realized the full possibilities of the 16-mm art until 
very recently. We have heard a description of a new 16-mm camera 1 
designed not for the amateur but for the professional one that can 
stand beside its big brother, the 35-mm camera, and do everything 
the latter can do except for such limitations as may be imposed by the 
grain size of the emulsion. 

With such a conception of the 16-mm camera it is logical to equip 
it with lenses in every way comparable to those used on the profes- 
sional 35-mm camera, and it was to make this possible that the series 
of lenses described in this paper was designed. 

This is a series of Baltar lenses containing focal lengths of 12.7, 
15, 17.5, 20, and 25 mm, of which the four latter focal lengths can be 
carried on the turret of the new Mitchell 16-mm camera. Their 
relative aperture is//2.3 for all focal lengths. They are designed to 
produce pictures not only equal in sharpness to those produced by 
the longer focus Baltars in the 35-mm cameras, but pictures that ex- 
hibit the same indefinable characteristics of excellence that produce 
an impression of something more than mere mechanical perfection. 

* Presented Oct. 23, 1946, at the SMPE Convention in Hollywood. 
** Bausch and Lomb Optical Co., Rochester, N. Y. 




Vol 48, No. 3 

The lens design is a familiar one consisting of four meniscus-shaped 
components with each of the two inner components consisting of two 
elements cemented together (see Fig. 1). Advantage has been taken, 
however, of new high index glasses, developed since the war began, 
to obtain practical perfection in the correction of spherical aberra- 
tion, astigmatism, and curvature of the field. Each lens in the series 
has been independently designed for the field of view it was required 
to cover with the exception of the 25-mm which is the same construc- 
tion as is used for the 35-mm film. In this case no improvement 
seemed necessary or possible for the 16-mm frame. 

We will now go into more detail in respect of performance and cor- 
rection of aberrations for the 17.5-mm lens, for this is the median focal 

FIG. 1. Bausch and Lomb Baltar 17.5-mm, f/2. 3 lens. 

length of the series. The residual spherical aberration is so insignifi- 
cant that when this iris is closed to//2.8 the image of a star is a pure 
diffraction pattern. Actual tests with red, green, and blue filters 
reveal no change in the plane of best focus and the difference in the 
size of the images formed by these three primary colors differs by not 
more than one part in a thousand. At the corners of the frame the 
images of tangential lines lie on the focal plane and for radial lines 
about 0.001 in. in front of it. In more technical language, the mean 
curvature of field is half a thousandth of an inch and the astigmatism 
one thousandth. 

The variation of chromatic aberration with distance from the axis 
or, to put it in another way, the variation of spherical aberration with 
wavelength is insignificant. This is a characteristic of lenses of this 
general type not found in any other type in so far as I know. While 


I do not recall having seen the history of this lens form traced back 
to Gauss' work on telescope objectives, it seems to me the line of 
descent is clear. Early opticians had several solutions to offer for 
disposal of the fourth variable presented by a two-element telescope 
objective after the three primary requirements of given focal length, 
corrected chromatic aberration, and corrected spherical aberration 
had been met. Gauss proposed that the fourth condition be that 
spherical aberration be corrected for two colors and showed that this 
condition could be met with two meniscus elements one positive 
and one negative ah 1 surfaces being concave towards the image 

In 1889, Alvin Clark, America's most accomplished telescope ob- 
jective maker, was granted a patent (USP 399,499) on a photographic 
objective consisting of four meniscus elements and comprising sub- 
stantially two Gauss telescope objectives mounted with all faces 
curved towards the diaphragm. This lens was manufactured by the 
Bausch and Lomb Optical Company for several years. 

The deviations from this basic construction are large in number 
and exceedingly diverse in performance characteristics. They in- 
clude process lenses, wide-angle lenses, and high-speed lenses. And 
they all approach reasonably well the original thought of Gauss, 
viz., that spherical aberration should be equally well corrected for 
two colors. 

The best efforts of the designers, however, are of no value unless 
the execution of the design in manufacture is equally carefully and 
competently controlled. One of the fundamental requirements in 
assembling a lens system is to achieve exact alignment on a common 
axis of all the lens elements. The commonest lens construction con- 
sists of a front member and a rear member, each mounted in threaded 
mounts that screw into the two ends of a lens barrel which contains 
the iris diaphragm. The difficulty of getting these units to screw to- 
gether so that the two members are truly coaxial is formidable. It is 
true that many excellent lenses have been made in this way but we 
think there is a better way. 

For these short focus lenses we have mounted each lens component 
in an individual cell with a smooth, cylindrical wall and the iris 
diaphragm in a similar way. Ring-shaped spacers are used where 
necessary .and the whole assembly is accomplished by pushing the 
components into a barrel the inside of which is a true cylinder, very 
accurately fitted to the diameter of the lens cells. The whole assembly 



Vol 48, No. 3 

is held in place with a single'retaining ring (A in Fig. 2). This is 
the manner in which we have mounted microscope objectives with 
the utmost satisfaction for many years and our experience convinces 
us that we can maintain coaxial alignment by this method to a higher 
degree than can be accomplished with the older method. 
The diaphragm actuating pin B is screwed in place after the 'as- 
sembly has been effected a set- 
screw, not shown in the diagram, 
is installed to lock the diaphragm 
ring in place, and the covering 
ring C, carrying the stop opening 

/ r\ scale, is slipped over the outside 

x-x QQ and held in place by the spring 

ring D. 

To v disassemble for cleaning, 
the ring C can be pushed off 
the mount, a setscrew that locks 
the diaphragm ring in place is re- 
moved, retaining ring A is re- 
moved, and the whole assembly 
can then be pushed out from the 

Finally, in order to reduce to a 
minimum the stray light in the image plane, all surfaces are coated 
with a hard, durable coating of magnesium fluoride. 


1 BAKER, F. F. : "A New 16-Mm Professional Camera", /. Soc. Mot. Pict. Eng., 
48, 2 (Feb. 1947), p. 157. 


MR. JESS DAVIS: Do these lenses have completely closing iris? 

DR. RAYTON : No, I do not think they do. 

MR. DAVIS: Didn't some of the 35-mm lenses have this feature? 

DR. RAYTON : Yes, some of them have been made with completely closing iris, 
but investigation into the matter some years ago indicated that the requirement 
was encountered in such few cases, so few people were interested in it, that we de- 
cided to discontinue it. A completely closing iris is possible only by exerting a 
quite undesirable force on the diaphragm leaves, so it was discontinued. 

MR. HAWK: Can you tell us anything about coma in these lenses? 

DR. RAYTON: I am sorry I cannot tell you quantitatively. It is exceedingly 
small, a matter of hundredths of a millimeter. 

FIG. 2. 

Precision mounting fdr short- 
focus Baltars. 


DR. F. G. BACK: I would like to know about zonal spheric aberrations of the 
0.707 zone. 

DR. RAYTON: As I said in the course of the paper, by stopping the lens to//2.8 
it gives a pure diffraction pattern. From the standpoint of the use of the lens, 
that is the answer. It could not be any better. 

MR. J. A. LARSON: That is the critical aperture? 


MR. LARSON : I would like to ask whether it is not possible to expand the //- 
stop scale on lenses to the point where either half or third stops can be calibrated 
on them, or where the scale can be expanded to cover the full circumference of 
the lens? It is quite a problem from a practical standpoint to get //stops set 
correctly and usually when you are shooting exterior on Kodachrome, for example, 
the correct //stop runs between //8 and//ll, and often it lies between //ll and 
//16. It is a serious problem from a practical photographer's viewpoint to ex- 
pand that scale, particularly in the smaller stops, so that you can set the aperture 

DR. RAYTON: It is a real point, particularly in short focus lenses. Perhaps 
Mr. Baker could answer the question as to how that is handled in the focusing 
mounts employed on the Mitchell camera. 

MR. F. F. BAKER: In the new Mitchell mounts, the diaphragm scale is carried 
out to a very much larger diameter, similar to the other standard Mitchell mounts. 
This makes the spacing at least double what it is on the lens. 

MR. S. E. MOORE : In this connection we find you get quite a different exposure 
if you set the stop, say at// 11 or// 16, going from wide open to closing down than 
if you start with it closed down and open up. 

DR. RAYTON: That is a fact, and the only remedy is to approach the stop from 
the same direction at all times. If an iris diaphragm were made with precision 
and without any backlash, I do not think it could be operated. 

MR. MOORE: I wonder if it would be possible to use different pitch threads, 
so we would get about the same change in focus for the various focal length lenses, 
rather than using the same pitch thread and moving the lenses different angular 
distances? I believe the Fox camera has that. 

DR. RAYTON: I am inclined to think that angular movement is completely dif- 
ferent in these lenses from one focal length to another. The scales are propor- 

MR. MOORE: I was thinking of it particularly in connection with some auto- 
matic focusing device. Are the //stops calculated mathematically or calibrated 
in terms of transmission of light? 

DR. RAYTON : These are calculated mathematically. So far there has been no 
basis established on which we would feel safe in calibrating them photometrically. 
We can do it if and when such a basis is established. 

MR. C. R. SKINNER: I would like to ask if you would give us an approximate 
idea of how much the coating increases the transmission of this lens over a similar 
lens that is not coated? 

DR. RAYTON: In this particular lens, the coating increases the transmission 
about 28 to 30 per cent. However, I do not regard the increase in transmission 
as being the main reason for coating. It is the improvement of quality and bring- 
ing out detail in the shadows which you cannot obtain without it. 

216 W. B. RAYTON 

MR. J. A. MAURER: In looking at the diagrams of this lens, I note what seems 
to me to be one unusual characteristic, that the elements are relatively thinner 
than they have been in most six-element lenses, as made by Zeiss and other Euro- 
pean firms. Of course, we have in the paper the fact that there is another change 
in that the newer high-index glasses have been used. The literature states that 
the worst outstanding trouble in the design of such lenses in the past has been the 
higher order aberration known as oblique spherical aberration. I want to ask 
whether the use of the new glass and any other departures from the orthodox de- 
sign have made it possible to correct that specific aberration better than usual? 

DR. RAYTON : It is certainly reduced to a very low level in these lenses. Un- 
doubtedly the glass contributes to it. Every element in the design contributes to 
that final result. 


With the death of Dr. Wilbur B. Rayton on Oct. 31, 1946, while on 
a business trip to Los Angeles and San Francisco, the nation lost one 
of its top-ranking optical engineers. While in California he attended 
the Hollywood Convention of the Society of Motion Picture Engi- 
neers and presented a paper on 16-mm lenses, published in this issue. 

As a member of the Bausch and Lomb Optical Company Scientific 
Bureau since 1908, and its director since 1926, Dr. Rayton was ac- 
tively interested in all phases of the optical industry and contributed 
definitely to the development of optical systems in the fields of human 
vision, microscopy, photography, gun fire control, and particularly 
to the requirements for optical devices in the field of motion pictures 
in all its ramifications. It is hard for one who has been so closely as- 
sociated with him for so many years to say that his ability was more 
outstanding in one field than in another because of his recognition in 
so many fields, but he was recognized as one of the leading authorities 
on optical systems for gun fire control, and only two months before 
his death was awarded the Navy Ordnance Development Award for 
"Distinguished Service to Research and Development of Gun Fire 
Control Equipment" during World War II. 

Among his many other accomplishments, Dr. Rayton was a lens 
designer of outstanding ability, and particularly so in the photo- 
graphic field. He was interested in aerial photography and aerial 
mapping. He designed a number of the very long focus telephoto 
lenses used during World War II and designed the now well-known 
Metrogon lens, which has become the standard for use in aerial map- 
ping in conjunction with multiplex equipment. 

Dr. Rayton was early interested in the problems of motion picture 
photography and became active in the Society of Motion Picture En- 
gineers in the early days of its organization. He was elected a Fellow 
of the Society on Jan. 1, 1934. Dr. Rayton contributed greatly to the 

* Manager, Scientific Instrument Division, Bausch and Lomb Optical Com- 
pany, Rochester, N. Y.; received Feb. 20, 1947. 


218 I. L. NIXON Vol 48, No. 3 

rapid improvement of the art from the standpoint of designing both 
lenses to make better motion pictures and optical systems to project 
better motion pictures. He was particularly intrigued by the pos- 
sibility presented in the early days of sound recording and reproduc- 
tion on film and in the need for better illumination and optical pro- 
jection systems. His contributions in this direction included such 
items as the now famous Baltar lens for the professional 35-mm 


cameras and the equally famous Super Cinephor lens so extensively 
used in the leading theaters throughout the country. His other de- 
velopments in this field were special reflectors and condenser systems, 
polarizing photometer for measuring light intensity and density. 

In addition to the direct developments which he contributed,, he 
gave generously of his time both as a contributor of special articles 
published in the JOURNAL and other technical journals and to serving 
on executive boards and committees. In 1932 he was on the Fellow- 
ship Committee which decided to have the University of Rochester 
work on the subject of visional fatigue. A paper was prepared by 

March 1947 WlLBUR B. RAYTON 219 

P. A. Snell on "An Introduction to the Experimental Study of Visional 
Fatigue", published in the May 1933 JOURNAL. 

He was actively connected with the Standards Committee and took 
part in establishing many standards prepared by this group. One of 
the things which interested him greatly was the glossary section, and 
even at the time of his death he had certain problems which he was 
studying in this connection. He was more recently a member of the 
Theater Television Projection Practice Committee and gave valuable 
advice in this capacity. He was chairman in 1931 of the Projection 
Theory Committee and was a member of the Screen Brightness Com- 
mittee, the Projection Practice Committee, and Sound Committee. 

Another problem in which he was most recently interested was 
photometric calibration of lens speeds, and that problem was a sub- 
ject of discussion with a special committee on his recent West Coast 
trip. He believed sincerely that this offered a consistent method of 
calibration of lenses for standardizing light transmission. Unfor- 
tunately, his untimely death prevented continuing his study and final 
recommendation, but it is to be hoped that this problem can be car- 
ried on by other committee members, who can be assured of the as- 
sistance in this direction from Dr. Rayton's associates in Rochester. 

It was my great privilege to be intimately associated with Dr. 
Ray ton during all of his years with the Bausch and Lomb Optical 
Company, and in his death comes a loss not only of a great engineer, 
but of a man whose devotion to truth and the advancement of science 
could never be questioned. 


Summary. This paper outlines the tools and means that are at the disposal of the 
motion picture production mixer to enable him to fulfill his prime responsibility of 
being the director's assistant in all matters pertaining to sound. A parallel is drawn 
between the work of the soundman and the cameraman. Particular emphasis is placed 
on the artistic capabilities and qualifications required by the mixer to ensure the degree 
of confidence and co-operation that must exist among the soundman, the director, and 
the cast in order that sound may contribute its full share to the realistic quality of the 
final product. 

With the introduction of sound into motion pictures, revolution- 
ary changes took place in all branches of the industry. The silent 
picture had relied upon pantomine and printed titles to tell its story. 
Now, with the addition of the spoken word, musical accompaniment, 
and realistic sound effects, the motion picture presented to the public, 
for its enjoyment and education, real life as experienced by each of us 
from day to day. 

This new medium of expression called for new techniques in writing, 
acting, photography, set design, stage construction, laboratory proc- 
essing, and all the many phases of motion picture production. A new 
science, the science of the transmission and recording engineer, had 
wrought a change in an art and only by the complete and proper 
welding of this science and art could the motion picture realize its full 
capabilities. 1 

During the twenty years of its growth, therefore, it is to be expected 
that the sound picture would produce many and varied changes in the 
personnel manning its production staffs and crews. By no means the 
least significant of these has been the evolution of the sound engineer 
from a man of mathematics, transmission circuits, recording equip- 
ments, and gadgets, with a foreign language of decibels and gammas, 
to the artist in whose hands rests the full dramatic impact which 
sound can impart to the motion picture of today. 

* Presented Oct. 21, 1946, at the SMPE Convention in Hollywood. 
** Warner Bros. Pictures, Inc., Burbank, Calif. 



Who is this sound engineer who has contributed so much during the 
past twenty years to the revitalization of the motion picture indus- 
try ? What are his functions, and what does he accomplish ? 

First, let us glance at the organization of a typical sound depart- 
ment. This group is headed by the director of sound recording, whose 
position is both administrative and technical in character. He has 
complete authority with respect to the operations of his department, 
and it is his responsibility to secure the best recording possible at a 
reasonable cost of operation under a wide variety of recording condi- 
tions. He must co-ordinate the technical efforts of his department 
with the functions of other studio groups, and he is vitally concerned 
with the quality of sound reproduction of his product in the theater. 
In handling the many operations with which his department is con- 
cerned, he is assisted by a chief engineer, who is responsible for all 
of the technical phases of sound department operation, including the 
installation, operation, and maintenance of studio recording and 
reproducing equipment and the development of improvements in 
technical facilities. 

The functions of the personnel of the department may be roughly 
divided into four major classifications : 

(a) Production recording; 

(&) Music recording; 

(c) Rerecording or dubbing; 

(d) Engineering and maintenance. 

The operating groups in each of classification (a), (b), and (c) are 
headed by men known as "mixers", a designation derived from their 
operational function of mixing together the various sounds picked up 
by a number of microphones, or transmitted to a control panel from 
an assortment of sound tracks during the rerecording process. 2 It is 
with the mixers that we are here primarily concerned. 

These men were originally recruited largely from the telephone and 
radio engineering fields, and in the majority of cases have reached the 
present state of efficiency in their art as a result of fifteen or twenty 
years of training and experience in the recording of sound for motion 

Let us consider the production mixer. In the early days of sound 
recording, one of the greatest limitations imposed upon the director 
was the restriction in movement of the actors by virtue of their having 
to speak in specified fixed positions at which microphones were 

G. R. GROVES Vol 48.. No. 3 

suspended and hidden from the camera view. The only way in which 
an illusion of freedom of movement could be obtained was by the use 
of many microphones positioned along the path traveled by the 
actor. By smooth fading or switching from one microphone to 
another, a reasonably smooth and continuous recording was obtained. 

Of necessity, this type of microphone pickup technique required 
that the mixer be extremely expert in the noiseless, rapid, and accu- 
rate manipulation of the microphone switches and controls. The actor 
had to speak the dialogue exactly as written in the script, word for 
word, and switching from microphone to microphone had to be ac- 
complished with split-second timing between words and during 
pauses for breath. The mixer's attention was focused entirely on the 
operation of his equipment ; and if the dialogue could be understood 
and was recorded with sufficient volume, all was well. 

With the development of microphones that could be used at some 
distance from their associated amplifiers, and with the advent of mi- 
crophone booms that could move the microphone rapidly and si- 
lently about the set, 3 the fetters were gradually removed from the 
director and actor until today scenes are staged with no restriction 
whatsoever from the recording system. 

Let us briefly review the tools and means that are at the disposal 
of the soundman to allow this freedom of movement and to help him 
create the illusion of reality upon the screen. 

First and foremost, of course, is the microphone, which may be 
regarded as the ear of the recording system. But there is one great 
difference between the microphone and the human ear. The human 
ear has a brain, while the microphone is a robot. The ear is the means 
of transmitting outside sounds to the brain, which selects that which 
we wish to hear, and within reasonable limits, discards the rest. This 
faculty of concentration makes conversation possible in the midst of a 
crowd at a football game and enables us to select, from amongst sev- 
eral voices all talking together, the voice we wish to hear. The fact 
that we have two ears and the fcinaural sense of hearing aids this power 
of concentration by enabling us to identify the location of a source of 

A microphone has no such powers of discrimination, and picks up 
all sounds equally well within its range. It is necessary, therefore, for 
the soundman to create, artificially, conditions surrounding the micro- 
phone, so that it picks up only those sounds which he wishes to be 
heard, In creating these conditions the soundman becomes the brain 

March 1947 THE SOUNDMAN 223 

of the microphone. For example, the loudness of extraneous noises 
such as footsteps, traffic noises, and crowd noises, must be reduced to 
a level which sounds unnaturally low to the ear in order to sound like a 
natural background through the microphone. To simulate further a 
sense of concentration, the microphone itself has been designed to 
have directional properties. 

Various types of microphones are available for the soundman's use, 
depending upon the conditions under which they are to be used and 
the type of material to be recorded. The unidirectional microphone 4 - 5 
is so designed that it has a maximum sensitivity to sound waves origi- 
nating in the front or operating side of the microphone, while sounds 
generated at the rear of the microphone are considerably attenuated, 
giving approximately a 10:1 ratio of desired to undesired pickup. 
This type of microphone is, therefore, most useful in reducing the 
level of such undesirable noises as camera noise, floor squeaks, dolly 
noises and sounds reflected from walls and other reflecting surfaces. 6 

The dynamic-type microphone also is widely used in production 
recording. 7 While fundamentally nondirectional, it may be given 
certain directional characteristics by the addition of directional baf- 
fles mounted in front of the microphone diaphragm. This type of 
microphone is usually smaller and lighter in weight than the unidi- 
rectional microphone, and is less sensitive to and more easily protected 
from wind pressures, with their resulting thudding and thumping 
noises. This microphone is, therefore, most suitable for exterior 
work, and its light weight permits it to be suspended from the end of 
a hand-held pole where the shooting conditions do not permit the use 
of a microphone boom. Long dolly shots, the cramped interiors of 
boats, airplanes, automobiles, and small sets are examples of such 

A third type of microphone, widely used in the recording of music, 
is the velocity- or ribbon-type microphone. 8 This microphone may 
be termed "bidirectional" in that sound waves approaching it from 
either front or back have the maximum effect, while sounds approach- 
ing from the sides have little or no effect upon it. Its directional char- 
acteristic being practically independent of frequency, it is admirably 
suited for high-quality music recording work. 

A number of sound concentrators 9 have been designed, and while 
the quality of sound picked up by them is inferior in some respects to 
that obtained with standard microphones, they have "been used quite 
successfully in recording sound effects where the source of sound might 

224 G. R. GROVES Vol 48, No. 3 

be in some inaccessible place or where extreme segregation of wanted 
from unwanted sounds is necessary. 

It happens in the recording of sound for motion pictures that ex- 
traneous sounds may occur which are detrimental to the scene and 
are beyond the control of the mixer. For example, during the record- 
ing of exterior scenes, airplanes may pass overhead, wind may cause 
excessive rustling in the trees, quiet lapping of surf at the beach may 
turn into pounding waves. Here the director is dependent on the 
soundman's judgment for the best procedure from both the artistic 
and economical standpoint. 

As previously mentioned, the microphone is a one-eared device 
which causes the apparent loudness of off-stage sounds to be exagger- 
ated. The soundman, therefore, is the only one who can say whether 
extraneous sounds are unduly loud or annoying or detrimental to 
the scene. The soundman must decide whether such disturbance jus- 
tifies another take, whether the disturbing noise could be eliminated in 
rerecording or whether it would be more economical to "post-syn- 
chronize" the scene. 

When the soundman decides that it would be most advantageous to 
post-synchronize the scene, the recording that he makes while the 
scene is being photographed serves merely as a cue track which is 
played back to the actors at some later date and serves as a guide to 
them in synchronizing a new sound track to match the picture. The 
post-synchronizing work is done in a special recording room where the 
soundman has means for controlling the acoustical conditions so as to 
enable him to match the acoustical conditions prevailing at the time 
of shooting the original material. 10 

A number of auxiliary aids are available to the soundman to adapt 
his microphones further to unusual shooting conditions. He may use 
a fine-mesh silk cover, called "wind-gag", to enclose the microphone 
completely as a protection against wind; or he may use a specially 
designed sound absorbing waterproof hood over the microphone as a 
protection against rain. Special electrical networks, known as 
equalizers, can be used to change the character of the sounds picked 
up by the microphones, filters are used to attenuate or even eliminate 
certain sounds, 11 electronic compressors 12 may be inserted into the 
recording system to assist in keeping the lowest spoken syllables and 
the loudest shouts within comfortable audible range for the listening 
audience. 13 

Having determined the type of microphone to be used, microphone 

March 1947 THE SOUNDMAN 225 

placement, like camera angle, must be carefully chosen. The camera- 
man paints his picture with lights and shadows composition and 
perspective are carefully chosen a mood is created. And so with 
the soundman, acoustic conditioning of the set for optimum sound 
quality is done ; correct sound perspective is secured ; the necessary 
degree of sound "presence" to match the photographed image is de- 
termined; the loudness of extraneous sounds is so established as to 
create a sense of concentration upon the wanted sounds without losing 
the effect of reality. In other words, a sound picture is painted 
which, in all respects, is complementary to the optical picture cap- 
tured by the camera lens. 

While the cameraman is concerned solely with the quality and 
quantity of reflected light, the soundman is concerned with the qual- 
ity and quantity of both incident and reflected sound and only by a 
critical and judicial blending of the two can the illusion of true sound 
perspective be obtained. 

It may happen that considerations of cost and construction dif- 
ficulties preclude the use of materials in the design of a set which will 
permit suitable acoustic characteristics. For instance, it would be 
impractical to build a cell block of concrete or a subterranean cave of 
rock. In such cases, the soundman resorts to the use of reverbera- 
tion chambers and acoustic labyrinths which enable him to add any 
desired degree of reverberation to his recordings. 14 But should the 
reverberation in his original material be excessive, it can never be 
removed, and consequently is to be avoided at all costs. 

Close collaboration is, therefore, required between the soundman 
and the art director during the planning and construction of sets. 
Large parallel surfaces must be avoided ; deep recesses and alcoves 
in which dialogue may be spoken must be acoustically treated to 
prevent the speech from sounding "boomy"; large glass reflecting 
surfaces may have to be substituted with fine-mesh silk cloth; ceil- 
ings visible to the camera must be made of sound-transparent mus- 
lin; overhead beams that may interfere with movement of the 
microphone must be made removable. And so the production sound- 
man sets the stage, the acoustical pattern is set, the microphone si- 
lently follows the actors about the scene, twisting and turning to 
catch each whispered word and registering every tiny inflection with 
true fidelity, weaving in and out to avoid casting shadows from the 
multiplicity of lights, raising and lowering to preserve correct per- 

226 G. R. GROVES Vol 48, No. 3 

In present-day motion picture practice, the great majority of 
scenes are recorded with a single microphone. At first glance this 
would seem to indicate that the work of the mixer has been greatly 
simplified, but this is not the case. 

Simultaneously with the improvements in the production record- 
ing equipment, have come improvements in reproducing equipments 
which, in turn, have called for infinitely greater attention to those 
factors which contribute to life-like portrayals of character on the 
screen. First and foremost, the mixer of today is concerned with 
"performance". Not the performance of his equipment this is as- 
sured by competent maintenance crews, skilled microphone boom and 
recording machine operators but with the performance of the actors 
and musicians whose art he is preserving. 

The prime function of the mixer of today is to be the director's 
assistant and advisor in all matters pertaining to sound. To fulfill this 
capacity adequately he must necessarily be as familiar as the director 
and cast with all phases of the script. He should be thoroughly fa- 
miliar with the plot, the dialogue, the characterizations to be portrayed 
and the locale and geography of each individual scene. He should ap- 
preciate the mood and tempo in which scenes are to be played and 
should always be conscious of what the effect will be on the scene he 
is recording, of the music and sound effects that will be added later in 
the rerecording process. 

Often, directors will devote early rehearsals to a discussion of the 
significance, distinguishing qualities, merits, and demerits of the 
script. During these early discussions between the director and his 
cast, the soundman should always be present, seeking an understand- 
ing of all the characters, the setting of the play in time and place, the 
historical background, the customs of speech and the mannerisms of 
the era, and above all, the thoughts and psychology that lie behind 
the spoken words. Having thus obtained a comprehensive picture of 
the scenes he is to record, and having secured a complete understand- 
ing of the director's desires, it is the soundman's function to observe, 
purely by what he hears in his monitoring headphones, whether by 
voice pitch, loudness, tempo intensity, emotional quality, and mood, 
the actor is delivering the performance desired by the director. 

Since it is common practice, for reasons of economy and expediency, 
to shoot scenes out of continuity, the soundman must exercise the 
keenest judgment in matching the quality of sound performance from 
day to day. He must thus assure a smoothness in the finished 

March 1947 THE SOUNDMAN 227 

product that will convey the impression of the whole picture being 
made as one continous play-like performance. 

While critically monitoring the scene being recorded, the soundman 
must see that there is no obvious effort on the part of the actor at so- 
called tone production and theatrical voice projection. There must 
be no obvious cultivation of careful diction. The mannerisms of 
speech must be those of the character delineated. The soundman 
must carefully draw the line between poor articulation that will result 
in lack of audience understanding of the story and pedantic artificiali- 
ties that will destroy the illusion of reality. The soundman can 
quickly detect such faults in speech delivery as huskiness, nasality, 
throatiness, breathiness, where these characteristics are not required 
and result from faults in breathing, nervousness, superficiality of read- 
ing, an unemotional state of mind, or fatigue. Conversely, he can 
equally well detect the lack of these characteristics where they are 
necessary attributes to the characterization involved. 

Since most scenes are shot with one camera, it becomes necessary 
for the actor to repeat his performance many times in order to obtain 
coverage of the scene from a number of camera angles. This frequent 
repetition of the same dialogue can often result in a too glib reading of 
the lines, and the consequent superficiality of the scene becomes im- 
mediately apparent to the soundman. Since all the mixer's critical 
faculties are concentrated upon one thing the sound of the scene no 
one is better able than he to appreciate whether the actor is maintain- 
ing the feeling of spontaneity in his performance. Even though the 
scene may be rehearsed and played many times before the purely me- 
chanical details of the shot may be considered perfect, at no time 
must the soundman permit the "illusion of the first time" to disappear 
from his recordings. 

In many screen plays, the story covers the span of life of one or more 
characters. Here the soundman is confronted with the problem of 
guiding the actors through a smooth and logical aging of the voice. 
Make-up, costuming, and physical mannerisms can satisfy the eye in 
presenting an authentic visual passing of the years. The soundman 
must rely on a sensitive ear and keen judgment to be assured that the 
auditory illusion of the passing of time is equally convincing. 

Outstanding examples of successful co-ordination of physical and 
aural aging have appeared in the performances of Paul Muni in 
"Louis Pasteur", Robert Donat in "Goodbye Mr. Chips", and Bette 
Davis and Claude Rains in "Mr. Skeffington". 

228 G. R. GROVES Vol 48, No. 3 

In the shooting of pictures involving dual roles such as the two roles 
of "Kate" and her sister "Patricia", played by Bette Davis in "A 
Stolen Life", the difference in character of the two girls is largely 
dependent upon the differences in pitch, inflection, and tempo of their 
voices. In maintaining these individual characteristics, reliance was 
placed on the critical faculties of the mixer. He had to be certain 
that the differences once established were maintained from scene to 
scene and day to day. 

It is frequently necessary for the soundman to see that voice quality 
and loudness conform to the geographical specifications of the scene. 
For instance, in the Warner Bros, picture "Cry Wolf", Barbara 
Stanwyck is thrown from her horse while riding in a lonely part of an 
estate. She is suddenly surprised by a man, her husband, whom she 
had thought dead. This scene could have been played in a fairly 
loud excitable voice, but when it is disclosed that the scene takes place 
near a caretaker's lodge in which her husband had been kept prisoner, 
we understand why the scene is played in the quieter and more emo- 
tional low, restrained voice. 

It is the business of the actor to present to an audience overt be- 
havior patterns which go under the name of emotion. The actor 
realizes that his voice is probably his most essential tool in reproduc- 
ing these behavior patterns and it is to the soundman, therefore, that 
he looks for advice, assistance, and criticism in his efforts to create the 
inner life of the character he is portraying. Only by the closest co- 
operation among the director, the actor, and the soundman, and by 
the free and tactful interchange of ideas between them, can the last 
foot of film be sent to the laboratory for processing with the assurance 
that all is "OK for sound" 


1 COFFMAN, J. W. : "Art and Science in Sound Film Production", /. Soc. Mot. 
Pict. Eng., XIV, 2 (Feb. 1930), p. 172. 

2 GOLDSMITH, L. T. : "Rerecording Sound Motion Pictures", /. Soc. Mot. Pict. 
Eng., XXXIX, 5 (Nov. 1942), p. 277. 

3 RYAN, B. F., AND SMITH, E. H.: "A Small Microphone Boom", /. Soc. Mot. 
Pict. Eng., 45, 6 (Dec. 1945), p. 441. 

4 LIVIDARY, J. P., AND RETTiNGER, M. : "Unidirectional Microphone Tech- 
nique", /. Soc. Mot. Pict. Eng., XXXII, 4 (Apr. 1939), p. 381. 

6 MARSHALL, R. N., AND HARRY, W. R.: "A Cardioid Directional Micro- 
phone", /. Soc. Mot. Pict. Eng., XXXIII, 3 (Sept. 1939), p. 254. 

6 THAYER, W. L.: "Solving Acoustic and Noise Problems Encountered in 

March 1947 THE SOUNDMAN 229 

Recording for Motion Pictures", /. Soc. Mot, Pict. Eng., XXXVII, 5 (Nov. 1941), p. 

7 MARSHALL, R. N., AND ROMANOW, F. F. : "A Non-Directional Microphone", 
Bell Sys. Tech. Jour., XV, 3 (July 1936), p. 405. 

8 OLSON, H. F. : "The Ribbon Microphone", /. Soc. Mot. Pict. Eng., XVI, 6 
(June 1931), p. 695. 

9 DREHER, C. : "Microphone Concentrators in Picture Production", /. Soc. 
Mot. Pict. Eng., XVI, 1 (Jan. 1931), p. 23. 

10 MUELLER, W. A.: "Dubbing and Post-Synchronization Studios", /. Soc. 
Mot. Pict. Eng., 47, 3 (Sept. 1946), p. 230. 

ENCES: "Motion Picture Sound Engineering", D. Van Nostrand, Inc. (New 
York), 1938. 

12 AALBERG, J. O., AND STEWART, J. G.: "Application of Nonlinear Volume 
Characteristics to Dialogue Recording", /. Soc. Mot. Pict. Eng., XXXI, 3 (Sept. 
1938), p. 248. 

13 MUELLER, W. A.: "Audience Noise as a Limitation to Permissible Volume 
Range of Dialogue in Sound Motion Pictures", /. Soc. Mot. Pict. Eng., XXXV, 
1 (July 1940), p. 48. 

14 RETTINGER, M.: "Reverberation Chambers for Rerecording", /. Soc. Mot. 
Pict. Eng., 45, 5 (Nov. 1945), p. 350. 


Dr. J. G. FRAYNE : I would like to ask what sort of an educational background 
would be necessary to produce this apparent superman. 

MR. GROVES: Our directors and producers feel that the soundman should 
have an education in dramatics. The question is always asked, "Should the 
soundman be an engineer?" I think the combination of the two would be ideal. 
The men who are now in the studios doing this work have had training in the 
best dramatic schools that can possibly be found, I think. As I said at the 
beginning of the paper, they have been working now for 15 or 20 years at this 
particular type of work, and they cannot help but have learned something from 
all the different types of actors, directors, and producers with whom they work. 

Where a man would start out from scratch to become this kind of a man would 
be a problem. I do not think he could do it, really. The only place he could do it 
would be in the studio. 

DR. FRAYNE: Isn't it possible some courses could be established in our uni- 
versities which would lead to this? 

MR. GROVES: Definitely yes, it would be a combination of engineering, cover- 
ing the use of the equipment that is used, and also, of course, dramatics. The 
training would be equivalent to an engineering course plus the type of training 
that the average dialogue director gets. In fact, I think that a mixer should be the 
dialogue director. That is the sum and substance of the whole thing a dialogue 
director with an engineering background. 

MR. J.I. CRABTREE : To what extent is post-recording used? Are songs always 
post-recorded, or are they ever recorded at the time the picture is taken? 

MR. GROVES: As far as songs are concerned, very few of them are post- 

230 G. R. GROVES 

recorded. They are mainly prerecorded. That is, the song is recorded before 
the picture is shot, and the person is photographed mouthing to a playback of the 
prerecorded music, but post-synchronizing is used where, for some reason or 
other, it is impossible to get a sound recording at the time of photographing the 
scene. Then, the track is t recorded in synchronism with the photographed pic- 
ture. All foreign versions are made with a post-synchronizing technique. Some- 
times an original sound track is used as a cue track and played back to the actors 
under more favorable conditions to obtain a better sound track. That is being 
used more and more. 

MR. JOHN HAWKINS: I wonder if you would comment on the difficulty of com 
munication between the mixer who speaks one language, the musical director who 
speaks another, the director of the set who speaks another, and lastly the pro- 

MR. GROVES: I do not believe that a mixer on a production company, who is 
qualified to be responsible for the sound on that production, will necessarily speak 
a different language from the director. I think in most cases they do speak the 
same language, but it is quite possible in the music scoring work that they will 
speak a different language. The scoring mixer, I believe, should have quite a 
musical education, musical training, and should be fairly well conversant with 
orchestration so he can talk the language of the musicians. If he can speak their 
language, he necessarily inspires much more confidence, and they believe his 
criticisms of balance, and often will change orchestrations to obtain greater clarity 
in the recordings. I think it is very essential that the scoring mixer be able to 
speak the language of the musicians. 




Summary. All present 16-mm film splices standardized by the Society of Mo- 
tion Picture Engineers, while possessing the necessary strength, have the undesirable 
characteristic of being visible on the screen. A new splice has been developed^ which 
does not encroach on the picture aperture area, and nevertheless retains sufficient 
strength for printing and projection operations. The principle, equipment, and 
abuse tests are described. 

At the present time there are three basic types of 16-mm motion 
picture film splices. These three types of splices are represented in 
the standards and proposed standards of the Society of Motion Pic- 
ture Engineers. W. H. Offenhauser's "Report of the Subcommittee 
on 16-Mm Film Splices", presented at the Technical Conference in 
New York in May 1946, x very aptly reviews the situation. There is 
a volume of approximately four hundred million linear feet of 16-mm 
release print produced per year. These four hundred million feet 
bear not only the picture and sound track, but also the printed image 
of every splice made in the original picture film, regardless of whether 
this original was a 16-mm negative or a 16-mm reversal positive. 
The prints also bear the splices which are made in the printing stock, 
and later the splices made in the print itself. 

The printed image of the splice does not constitute a problem in 
35-mm sound film production, because the width of the frame line 
has been standardized at 0.117 in., within which dimension it is pos- 
sible to make a strong splice. The frame line is masked by the pro- 
jector aperture plate and consequently the image of the splice does 
not appear on the screen. However, in 16-mm film the adjacent 
frames are photographed with a separation of only 0.006 in. The 
projector aperture, being slightly smaller than the camera aperture, 
increases the effective width of the frame line to 0.016 in. In 16-mm 

* Presented Oct. 25, 1946, at the SMPE Convention in Hollywood. 
** Signal Corps Photographic Center, Long Island City, N.Y. 
t DeFrenes and Company Studios, Philadelphia, Pa. 




Vol 48, No. 3 

projection, the picture frame line of 0.006 in. plus a margin of 0.005 
in. on both sides of the frame line are not visible on the screen. An 






























FIG. 1. The dimensions of the invisible 16-mm splice. 

attempt to imitate 35-mm practice and to splice within the effective 
frame-line width would fail because of the impractical weakness of a 
splice only 0.016 in. in width. 



If we examine the existing three basic types of splices in relation to 
these figures, we find that in the case of the widely used 0.100-in. 
straight splice an overlap of 0.042 in. will be visible on the screen on 
two successive frames. In the 0.070-in. straight splice, an overlap 
of 0.027 in. will be visible on the screen on two successive frames. In 
the case of both the 0.070-in. curved splice and the 0.070-in. diagonal 
splice, even greater overlaps are experienced. 

The function of a splice is to join two pieces of film together, and in 
doing so the splice must possess sufficient strength to withstand the 

FIG. 2. The cutter blades and bar. 

strain of printing and projection operations. However, inasmuch as 
the splice is a mechanical device which adds nothing to the context or 
enjoyment of the film, it should be as unobtrusive as possible or 
preferably invisible on the screen. , 

The authors, in co-operation with the Signal Corps Photographic 
Center, arrived at one solution to this problem of producing a 16-mm 
splice which would be invisible on the screen and yet retain a practical 
strength for printing and projection operations. Such a splice is il- 
lustrated in Fig. 1 . It will be noted that the splice is cut in the form 
of a step. The film is cut above the sprocket holes, down the edge 
of the picture area, and across the top of the frame line. This allows 



Vol 48, No. 3 

the splice to be 0.016-in. wide in the center, therefore invisible on the 
screen, and 0.079-in. wide along both edges of the film which rein- 
forces the splice. The total area of the overlap is 0.023 sq. in., as 
compared with 0.037 sq. in. for the standard 0.070-in. straight splice. 
It was realized that the new invisible splice would be practical only 
if it possessed a strength equivalent to that of the conventional 16- 
mm splice. Therefore, tests were made to determine the relative 
strength of the new splice and the standard 0.070-in. straight splice. 
Averaging the destruction tests of a number of splices, it was de- 
termined that the new invisible splice would withstand a straight pull 

FIG. 3. The film parts and the assembled invisible 16-mm splice. 

of 23 lb, and the standard splice would withstand a pull of 25 Ib. It 
is interesting to note that a 38 per cent reduction of the overlap area 
in the invisible splice resulted in a reduced stress resistance of only 
8 per cent. A possible explanation of this high ratio of strength 
to overlap area is that the new splice is particularly well reinforced 
at the film edges where the greatest stress may be expected. 

A second test was conducted in which an invisible splice was 
mounted in a device which rapidly flexed the film in a manner which 
reproduced the action of the film in the loops above and below the 
pull-down claw of the standard 16-mm projector. The splice with- 
stood a series of 50,000 consecutive flexings without any apparent 


weakening. Such performance is certainly greatly in excess of any- 
thing required of the film splice in normal life. 

The operation of the standard splicing cycle remains unchanged 
in making the new splice. One piece of film to be spliced is clamped, 
emulsion side up, in the splicer and cut straight across in the conven- 
tional manner. It is then moved to an out-of-the-way position. 
The other piece of film is placed in the splicer, emulsion side up, and 
scraped. It is important that the film be scraped before cutting, for 
ease of operation. Film cement is then placed on the scraped film. 
The action of cutting this film with the step-shaped cutter blade and 
superimposing tne two pieces of film may occur in the same operation, 
as is often done in conventional splicers. Most existing splicing de- 
vices may be altered to make the new invisible splice by the replace- 
ment of the cutter blades and bar. Of course, it is possible and would 
be desirable to design a new splicer around this principle. 

Fig. 2 illustrates the modification of the cutter blades and bar. 

Fig. 3 illustrates the film parts and the assembled invisible splice. 

The invisible splice, as developed at Signal Corps Photographic 
Center, has recently been put into general use at that installation 
with completely satisfactory results. The equipment used was a 
modified standard commercial splicer. No special training was 
needed on the part of the operator. It is at present contemplated 
to adapt the invisible splice as standard Signal Corps practice for all 
original 16-mm film. 

The authors wish to thank the many departments of the Signal 
Corps Photographic Center for their co-operation and encouragement 
in the development of this splicer. 


1 "Report of the Subcommittee on 16-Mm Film Splices", /. Soc. Mot. Pict. 
Eng.,47, 1 (July 1946), p. 1. 


(The foregoing paper was read by W. H. Offenhauser, Jr., in behalf of the au- 

MR. C. H. DUNNING: In the case of Kodachrome raw stock, is it necessary to 
scrape both sides? 

DR. E. K. CARVER: Yes, it is. 

MR. DUNNING : Can you do the sort of scraping required for this splice on both 
sides of the film? 

DR., CARVER; As I understand it, you ca.u dq so, if you before you cut, 

236 E. BAUMERT AND J. V. NOBLE Vol 48, No. 3 

MR. DUNNING: Does the uneven contour of the splice cause the film to tear 
away at the sharp corners during projection? 

MR. OFFENHAUSER: I understand that the authors have made extensive 
bending and other tests to check the performance of this new form of splice. If 
the splice is carefully made, they seem to feel that there should be relatively little 
more difficulty with it than there is now with the present narrow 0.070-in. splice. 

With regard to picking up dirt, all splices are dirt traps and this form of splice 
would seem to be no better or no worse than others. The great advantage which 
would seem to far outweigh its disadvantages is that when this splice is used in 
original material, such as original reversal or original Kodachrome or Ansco Color, 
the splice can be almost completely invisible in the release print. 

MR. DUNNING : If this proposal is pushed to a conclusion, it would represent 
an excellent contribution to laboratory technique because it is certainly needed. 
Visually, there is nothing more irritating than a diagonal splice in a picture. 

MR. OFFENHAUSER: I quite agree with both thoughts, Mr. Dunning. 

MR. BOYCE NEMEC: I might add that the modified splicer was a Griswold. I 
have seen the splicer itself. No parts were added, just a little bit was taken away. 
In reply to Mr. Dunning 's question, the part of the film that normally comes up 
on the left-hand side of the splicer is the part that has the step in it. The step does 
not appear until the cement has been applied, and the right-hand side of the 
splicer is closed down. 

MR. GEORGE FULTON : I do not know too much about the splicer, but I did see 
numerous samples of splices on Kodachrome, and no particular problem involved 
was mentioned in splicing Kodachrome as against any other film. 

MR. NEMEC: I might add that the problem exists no matter how you make the 
splice with film that has emulsion on both sides. The splicer is no consideration 
one way or the other in that connection. 

MR. OFFENHAUSER: As Chairman of the Subcommittee on 16-Mm Film Splices, 
we have had two contributions within this single convention on the subject for 
which the committee wishes to express its thanks. Despite the value of these 
contributions, we feel that the 16-mm splice problem is far from solved, much 
work needs to be done. We want to get more people thinking about better 
splices. We would like to obtain at least four papers on this subject for the next 

MR. GEORGE LEWIN: During the reading of the paper, Mr. Offenhauser in- 
dicated some doubt about the dimension of the 16 mils. I was wondering whether 
you would want to put something in the record as to what the doubt was ? 

MR. OFFENHAUSER: I have not studied the proposed dimensions closely with 
regard to the effect of frame line shift that occurs in the camera. Our present 
standards call for a tolerance of =*= 0.005 in. for photographed frame line location; 
this figure was chosen as a somewhat unsatisfactory compromise. It seems to have 
been the thought of the committee studying the subject of frame line location in 
the 16-mm camera that a tolerance of 0.003 in. would be desirable but could not 
be readily obtained with many of the camera designs now on the market. Pro- 
fessional designs that have the claw and registration pin at the camera aperture 
can maintain this tolerance without too much trouble, but cameras such as the 
magazine and similar types which may have the movement claw as far away from 
the aperture as seven frames cannot be expected to do so. The difference is 


aggravated if film is left in the camera overnight or for longer periods between the 
time the first scene on the film roll is photographed and the last scene on the roll 
is photographed. Suitable allowance must be made for film shrinkage. 

At this moment, I am not prepared to say that this proposal will be entirely 
satisfactory although for splicing original 16-mm films it looks like the best pro- 
posal made so far. In any event, there is the question of practicable tolerances 
that need to be expressed. 


Summary. Although film splicers of conventional design produce serviceable 
splices when in the hands of experienced operators, they leave much to be desired in 
the way of operational ease. The splicer described in this paper is simple to use and 
because all operations are mechanized, including scraping the emulsion, good splices 
are assured. The 16- and 35-mm professional models are hot-splicers, having heating 
elements as integral parts of the stationary shear blade. 

The film splice has long been regarded, even among technicians, 
as a comparatively minor aspect of motion picture technology. 
Recently, however, the lowly splice became the subject of renewed 
interest, largely because the SMPE Film Splice Subcommittee of the 
Standards Committee under the chairmanship of W. H. Offen- 
hauser, Jr., brought the question into the open just six months ago. 
The report of the subcommittee said : " . . . with most existing splicing 
equipment the quality of the splice depends to a very large degree on 
the skill and dexterity of the operator". 1 The quality of the splice 
also depends on the quality of the film cement used and on the splicer. 

Then it is obvious that in any discussion of film splices or splicing 
we have three important factors to consider. 

(1) The splicer 

(2) The operator 

(3) The film cement 

Each of these three factors has a number of variables, and each of 
the variables can contribute toward either a good or a bad splice. 

For practical purposes we may avoid considering film cement in 
this discussion because it is one item over which we have very little 
direct control. Beyond using a cement recommended for a particular 
type of film and one that has given us good results in the past, we are 

* Presented Oct. 24, 1946, at the SMPE Convention in Hollywood. 
** Reeves Instrument Corporation, New York. 


almost at the mercy of the people who compound it. Film cement, 
too, is a fit subject for an entire paper, and a timely one, I might 
add. Any superficial discussion would serve no purpose here. 

The operator, as Mr. Offenhauser pointed out, is a very consider- 
able factor in making consistently good splices, but regardless of how 
well a splicer is engineered or how well it is manufactured, we cannot 
hope to eliminate entirely the possibility for error. As long as we 
are dealing with people, that will be true. But the designers and 
manufacturers of any piece of truly modern equipment can do a 
great deal in the way of functional design and simplification. They 
owe this obligation to the people who will ultimately have to use that 
piece of equipment, and in discharging that obligation, they must do 
all they can to make its operation simple and obvious to a novice 

These things were all considered in designing the new splicer. The 
chief aim, at the outset, was to take as many of the variables as 
possible (that is, opportunities for human error) , out of the control of 
the operator and build them into the machine. The next step was 
to design the machine so that the majority of the variables could be 
held to tolerances well within the limits necessary to turn out con- 
sistently good splices. 

To make the machine, rather than the operator, make the splice, 
that was the basic problem. 

The next step was to study all of the manually operated splicers on 
the market to find from that study, just which of the operations in 
making a splice needed close control, and with a view toward simpli- 
fication, to find out whether or not it would be possible to eliminate 
some of the precautions or controls normally observed. 

Simple though this study was, it yielded some interesting results. 

The sequence of operations of conventional splicers is not obvious 
to a beginner. It was felt that an improvement in that direction 
would be a distinct advantage and that it should certainly be possible 
to build a splicer that would indicate the operations in correct se- 

Clean sharp cut ends of the film are important. Not so much in 
the process of making the splice, but a ragged cut or a cut with 
raised burrs is well on the way toward becoming a torn splice in the 
projector. Most splicers on the market fortunately do a good job in 
this respect and except as a general precaution, there is little improve- 
ment to be expected here. 

240 I.I. MERKUR Yol 48, No. 3 

The overlap area on the emulsion side of the film that becomes the 
inside of the "sandwich" must be scraped smooth and all emulsion re- 
moved. A great variety of scraping tools are in use today; knives, 
razor blades, scissors or almost anything with a sharp edge. Most 
splicers, now are supplied with separate little scraping tools but they 
have a great tendency to get lost and the improvised replacement at 
hand is always inadequate. 

The study showed that, regardless of how well the rest of the opera- 
tions are performed, .unless the scraped area is clean clear to the 
edges beyond the perforations, and is flat, dry, and slightly roughened, 


FIG. 1. Ace-Reeves film splicer. 

a good splice is almost impossible to make. The rough surface, simi- 
lar to what the printing trades speak of as "tooth", in connection 
with paper, seems most essential in securing good adherence. 

The only answer here is to have the right kind of scraper built as an 
integral part of the splicer and to control the depth of cut to little 
more than a half-thousandth below the bonded surface of the emul- 
sion. Tests seemed to indicate that an even deeper cut would pro- 
duce a good strong splice, that had the advantage of being somewhat 
thinner, but lack of practical experience with such a thin splice made 
it seem advisable to continue on proved ground, at least for the 

After the cement is applied both pieces of film must be pressed 
firmly together while the cement actually welds them into one piece 


at the overlap area. Speed is important because the highly volatile 
solvents evaporate rapidly from the surface of the cement applied 
to the film, leaving an extremely thin skin resembling a blister. If 
this blister forms before the two films are joined, the splice will have 
a milky white appearance, and although it may seem strong at the 
time, it will most certainly break. A milky appearing splice, made 
on any splicer should be cut out and remade, because it is "stuck" 
together as though mucilage or glue had been used, rather than 
"welded" as it should be. 

Besides speed, it is essential that a uniform heavy pressure be ap- 
plied all over the splice area to force out any excess cement that may 
have been applied, and to assure that the weld is good over the entire 

The question of the width of the splice lap has been discussed at 
some length recently from the standpoint of encroachment on the 
picture area, and doubtless everyone's judgment of correct width is 
tempered by the seemingly obvious conclusion that a wide lap will 
give a strong splice. That is not necessarily true. A poor bond, 
regardless of the reason, will not make a good splice, no matter how 
wide the film lap. Experience with goo'd splices of several widths 
seems to indicate that the width of lap is relatively unimportant. 
The quality or durability apparently depend on securing a good bond 
or weld and provided there is enough of the film there to be spliced, it 
will hold. 

Practical considerations, of course, limit the width to some extent 
and until the SMPE recommends a new standard width, or the Splice 
Committee reports improvement can be achieved in another direc- 
tion, it will be best to stay with present lap dimensions. 

Where time is a worth-while consideration, a hot splicer is a dis- 
tinct advantage. Studios, laboratories, and exchanges make a great 
number of splices each day and a splicer, built to make a reliable 
splice under normal conditions will be able to make many more, at a 
faster rate with some improvement in the quality of the weld, by 
addition of a heating element to the stationary shear blade or anvil 
as we have built into ours. 

Many splices made on conventional splicers are torn or weakened 
when they are stripped from the alignment pins. This, of course, 
is particularly true if the splice was not well made, and might very 
well be considered as a blessing in disguise because in some measure it 
controls the quality of the work turned out. It was not purposely 


included as a desirable feature. Retractable alignment pins would 
eliminate this last source of splice trouble. 

To summarize, a good splicer should produce a clean cut, scrape 
the emulsion away thoroughly, and hold the film "sandwich" firmly 
all over the splice area. For best results it should have its own built- 
in heating element and should have alignment pins that can be with- 
drawn before the finished splice is removed. 

The Ace-Reeves film splicer was designed to meet all of these re- 
quirements together with that of simplicity and ease of operation. 
It is manufactured to tolerances well within the limits of accuracy re- 
quired by the discriminating user. 


1 "Report of Subcommittee on 16-Mm Film Splices", /. Soc. Mot. Pict. Eng. t 
47, 1 (July 1946), p. 1. 


DR. E. K. CARVER: Did you use a wet scraper? 

MR. MERKUR : No, it is a dry scraper. We emphasize that a wet splice is not 
as good as one made by dry scraping. 

DR. J. G. FRAYNE: Is this method of splicing only applicable to nitrate film? 

MR. MERKUR : It can be used on safety and nitrate film. We have four models. 
It takes in 16-mm and 35-mm, amateur and theatrical. 

MR. R. H. TALBOT: In the 35-mm splicer does the negative or Bell & Howell 
type of perforation fit cleanly, or do you have to wedge it on? 

MR. MERKUR: You do not have to do that. It is made so precise the film will 
go right over it. 

MR. TALBOT: Many splicers for 35-mm are correct for positive-type perfora- 
tion, but not for the negative perforation on positive films as in some color proc- 

MR. MERKUR: That is the reason we have four types of machines. When 
you use them in studios, you can use the type that is required for it. 

MR. TALBOT: Well, in the exchanges the same thing will hold. You will be 
splicing both films with the positive-type perforations and also certain color films, 
with negative types. 


Introduction. Some twenty years ago, at a meeting of the 
SMPE, T. E. Finegan, who was then associated with the Eastman 
Kodak Company, presented a paper to you on "The Development of 
Classroom Films". This was before the introduction of the "talking 
picture" to the classroom, and in fact, it was in the very early days of 
classroom films of any kind whatever. And yet, even as far back as 
twenty years ago, Mr. Finegan was able to present a number of salient 
principles which are as valid today as they ever were. Some of these 
principles have not only been validated but strengthened and sharp- 
ened up by the experience of the past twenty years, as I hope to show 
you during the course of this discussion. 

Definition of Classroom Film. Let us begin by defining the 
classroom film. The classroom film is not a feature film. Nor is it 
a theatrical short. It differs from a feature film in much the same 
way that a history textbook differs from an historical novel. Some- 
one who is making a study of the westward movement will find much 
useful material in Emerson Hough's famous novel, "The Covered 
Wagon". For a systematic treatment of the period, however, he will 
turn to a first-rate history textbook on the subject, such as Frederic 
L. Paxson's "The History of the American Frontier, 1763-1893". 
Both the novel and the textbook have their place. But the novel is 
not a textbook and the textbook is not a novel. Nor would it occur 
to anyone to say of Emerson Hough that he should have written text- 
books and of Paxson that he should have written novels. In the same 
way, the classroom or text film is not and should not be a feature 
film, just as the feature film is not and should not be a text film.' 

A classroom film is an integral part of the existing school curriculum. 

* Presented Oct. 16, 1946, at a meeting of the Atlantic Coast Section of the 
Society in New York. 

"* Associate Director of Research, Encyclopaedia Britannica Films Inc., New 


244 F. S. CELLIER Vol 48, No. 3 

That means that a classroom film on a given topic is made to fit into 
the curriculum between the discussions that normally precede and 
follow consideration of that topic. The classroom film is not made 
for the purpose of fitting into a three-hour program which begins 
with Donald Duck and ends with "The Lost Weekend". It contains 
material for schools presented in the way in which schools are ac- 
customed to handle that kind of material. 

Since the classroom film is a text film, and since it is as much an in- 
tegral part of the curriculum as the textbook is, it has certain quite 
special characteristics. To begin with, it is meaty. It is packed with 
information. It is made to stand many screenings, and must avoid 
elements that become boring on second or third acquaintance, such 
as jokes. 

Again, it starts cold. It needs no long motivating introduction for 
the purpose of getting the audience out of one mood and into another. 
The mood which the audience needs to appreciate the classroom film 
is created by the teacher before the film is screened, as "Using The 
Classroom Film" demonstrates quite clearly. 

A definition of the classroom film would be incomplete without a 
reference to authenticity. The classroom film must be absolutely 
authentic. It must contain facts, and these facts must be presented 
with the same scrupulous regard for scientific validity that applies to 
the writing of the most rigorous textbook. For this reason, no class- 
room film worthy of the name is released without the sanction of as 
eminent an authority or panel of authorities in the field as it is pos- 
sible to obtain. 

The classroom film should also reflect everything psychology has 
been able to discover concerning the nature of the learning process. 
The type of step -by-step progression, the nature and timing of re- 
capitulations, the decision to proceed inductively or deductively all 
these, and a host of other facts must be implemented in a classroom 
film if it is to be worthy of its name. 

Primary Purpose. The primary purpose of a producer of class- 
room films is to teach not to make films for films' sake; to teach 
by means of a powerful medium of communication, called the motion 
picture. It is as true of a text film as it is of a textbook, of course, 
that if its style is pleasant and fluent, it becomes easier to take. The 
producer of a classroom film, like the writer of a textbook, will there- 
fore give every attention to style and mode of presentation. But the 
criterion on which the textbook or the text film stands or falls is not 


that of style but rather that of whether the film does a teaching job or 

This being so, it becomes the task of classroom film producers to 
select subjects to the teaching of which the film medium can make a 
major contribution. Among the subjects one can mention in this 
connection are phenomena that are microscopic, or hidden, or rela- 
tively inaccessible to the average student. In "bringing the world 
to the classroom" as the slogan of Encyclopaedia Britannica Films 
has it, the classroom film producer has frequently selected such phe- 
nomena as what the villi do during the digestive process, or what goes 
on inside a beehive, or family relationships in China dynamic phe- 
nomena which the average student will never be able to go and look at 
himself. These the camera can record and quite literally bring to the 

Another contribution which the classroom film makes to the teach- 
ing process is to present dynamic generalizations vividly. One of the 
primary tasks of the classroom film is to make it possible for students 
to see the forest as well as the trees. It is not enough to know only a 
series of isolated facts about a given subject. These facts become 
truly meaningful only if the dynamic generalizations which give them 
interrelationship and significance are clearly understood. This the 
film can do with the stroke of an airbrush or a snip of the cutter's 

In making its contribution to the teaching process, the classroom 
film frequently takes phenomena which are superficially familiar to 
the audience and then organizes these and presents them in new ways 
so that the film highlights those aspects that make these phenomena 
make sense. From a gallery one can see Congress; through a film 
one can see Congress tick. 

Staffing. In the course of the twenty years that have passed 
since Mr. Finegan presented his paper on classroom films to you, 
experience has indicated that a very special type of staff member is 
needed to produce classroom films that really measure up in the class- 
room field. In his paper Mr. Finegan made the point that experi- 
enced teachers should sit in with writers of classroom films. His point 
was perfectly valid because it is obvious that only people who are 
thoroughly and intimately acquainted with the problems and the 
procedures of classrooms can produce material that is thoroughly 
useful in classrooms. Since the time that Mr. Finegan presented his 
paper we have gone a step further and have found that not only 

246 F. S. CELLIER Vol 48, No. 3 

should writers of classroom films sit in with practicing teachers but 
that they should themselves be practical teachers, 

Mr. Finegan also points out that cameramen should not be sent 
out to secure a scene without being accompanied by a director; and 
in this connection he specified that the director should have sat in 
with the writer and be thoroughly acquainted with the script. Here, 
again, the experience of the past twenty years has led us to the logical 
next step : Just as the writer and the teacher should be one and the 
same person, so the writer and the director should be one and the 
same person. 

The personnel experience of my own company, Encyclopaedia 
Britannica Films or EBF has been of great value to classroom film 
producers everywhere. As you will recall, the company was originally 
founded in 1929 as a Western Electric subsidiary, and was known as 
ERPI Classroom Films until 1943, when it became affiliated with 
The University of Chicago through its present parent company, 
Encyclopaedia Britannica. The personnel standards set up origi- 
nally and refined in the light of seventeen years' experience have re- 
sulted in the development of a brand-new figure in the motion picture 
world an individual who is, at one and the same time, an educator, 
a motion picture script writer, and a motion picture director. 

If you tell me that such animals are very rare, I will immediately 
agree with you. One of the most challenging problems which class- 
room film producers face is securing the services of men and women 
who will qualify on all three points : teaching, writing, and directing. 
The experience of Encyclopaedia Britannica Films has shown that the 
ideal person for this type of assignment is someone who has had wide 
classroom teaching experience, who holds at least a Ph.D. degree or 
its equivalent in the field of his specialty, who has done considerable 
graduate work in education, and who has been carefully and system- 
atically trained in all the relevant phases of motion picture crafts- 
manship. At EBF we prefer to give this training ourselves. 

After the most careful screening of applicants, we finally select 
people who seem to show the greatest promise in these directions. 
They are usually people who have used films fairly extensively in their 
own teaching experience. They are people who have "been around", 
they are men and women of substantial academic standing, and they 
are still young enough to learn the techniques of film language after 
they come with us. After two or three years of careful and detailed 
training they are able to operate as unit producers, with complete 


responsibility (under the supervision of our Research and Production 
Departments) for seeing a film through from its earliest inception to the 
finished 16-mm release print. 

Experience has shown since the beginning of instructional sound 
motion picture making that the writing and producing should be in 
the hands of a single individual. Writing should not be farmed out 
to educators who- have never made films and producing should not 
be farmed out to motion picture technicians who have never taught 
school. Many people have tried to do it that way ; and while they 
have frequently produced films in gorgeous technicolor, schools just 
have not been interested. A number of classroom film producers 
had to "lose^their shirts" before the field recognized that a classroom 
film should be seen through from beginning to end by a unit producer 
who is at one and the same time a teacher, a writer, and a director. 
It is also recognized today that the unit producer's work should be 
supervised by Research and Production Departments, headed up, if 
possible, by veterans in the 'field of classroom film making. Let us 
look at these functions of Research and Production. 

Research. The Research Department of an organization making 
classroom films conducts at least four types of research : Develop- 
ment Research; Continuity Research; Evaluation Research; and 
Utilization Research. 

(1) Development Research. Before a classroom film is made and 
even before the topic itself is chosen, careful and painstaking de- 
velopment research is essential to determine curriculum content, 
pupil enrollment, current teaching techniques, textbook coverage, 
and finally, to come out with a decision regarding specific areas 
where the motion picture would make a definite educational con- 
tribution. Research of this type involves far more than a mere 
statistical survey which could be adequately done by a competent 
clerk. First rank development research brings a mature educa- 
tional philosophy and a wide subject-matter competence to bear 
on statistical facts and trends. When it comes to interpretative 
educational research of this type, amateurs (even very sincere 
and well-meaning amateurs) just cannot make the grade. 

(2} Continuity Research. Once the topic has been selected, a vast 
amount of research needs to be conducted in the subject-matter 
field of the projected film. What holds true for the teacher in the 
classroom holds true for the writer of a classroom film he cannot 

248 F. S. CELLIER Vol 48, No. 3 

teach something unless he himself has thoroughly mastered it. 
And mastery includes more than a superficial acquaintance with 
the ABC's. Mastery includes an understanding of the topic's 
relationship to the subject matter which in the teaching process 
precedes and follows it, and its interrelationships with the rest of 
the curriculum as a whole. 

The unit producer must therefore, in a sense, 'go to school him- 
self in order to achieve the familiarity with the material which 
must necessarily precede his writing an acceptable classroom film. 
In this process he should rely heavily not only on the advice and 
suggestions of practicing teachers in the field, but also on the 
guidance of an eminent specialist in the field someone who is 
either a national or a world authority. At EBF we call this indi- 
vidual the "Collaborator". Each classroom film should bear the 
stamp of authenticity which only the sanction of a Collaborator of 
this type can give it. 

After the subject-matter for the film is selected, continuity re- 
search involves its organization into acceptable motion picture 
form. It is here that it becomes essential to have as the writer 
someone who is at one and the same time a teacher, and a motion 
picture craftsman. It is impossible to separate the two in the 
creation of the teaching tool which we call the classroom film. 

(3) Evaluation Research. Both during and after the production of 
a classroom film, a competent Research Department carries on re- 
search to evaluate the success with which the film does its intended 
teaching job. This involves carefully prepared experiments in 
actual classroom situations. 

The evaluation procedure should be so rigorously set up that 
the results of these experiments are reflected in the final version of 
the film or its subsequent editions. The company should have 
no hesitation in making drastic changes in presentation or in can- 
celling production altogether if evaluation procedures prove the 
film to be inadequate 

The Research Department should also keep abreast of and en- 
courage evaluation programs in related institutions, such as col- 
leges and universities. Such a company as Encyclopaedia Britan- 
nica Films has had a consultative connection with the conduct of a 
great many evaluation experiments under the aegis of the country's 
leading universities. 

(4) Utilization Research. Even though silent teaching films have 


been used for over twenty years, and sound films have been used 
in classrooms for some seventeen years, a great deal of work re- 
mains to be done for and with teachers in order to discover the best 
ways in which this relatively new teaching tool can be used in class- 
room situations. This type of research we call utilization research, 
and it should be understood as embracing both classroom films as a 
whole and specific classroom, films in particular. The film "Using 
The Classroom Film", with which this meeting was opened, is one 
example of the way in which a responsible classroom motion picture 
company makes a contribution to proper utilization. 

A program of utilization research would include experiments de- 
signed to establish the relationship between a given film and the 
grade level on which it makes its maximum contribution. This is 
not always easy to do. There is one film in the EBF library which 
was designed for the first few grades of the primary school, as you 
will notice immediately I screen it. It is called "Gray Squirrel". 
And yet this same picture has been used on all levels of the elemen- 
tary and high school and even in some universities. In fact, a pro- 
fessor of ecology at one of our outstanding institutions has said that, 
in his judgment, it is the best film on animal ecology ever made; 
and he regularly screens it before his advanced classes in the sub- 
ject even though the narration begins as you will hear: "Good 
morning, Mrs. Gray Squirrel!" 

Production. The responsibilities of a . realistically conceived 
production department in an organization which makes classroom 
films are determined to a large extent by the peculiar nature of the 
enterprise. In no sense of the word must the production department 
of a classroom film company be thought of as concerned exclusively 
with what one might describe as the technical aspects of picture mak- 
ing. Just as the research department has the final responsibility for 
the picture's content, the production department has the final respon- 
sibility for the picture's form. 

It therefore is production's responsibility to see that nothing un- 
producable gets into the continuity in the first place. It is also pro- 
duction's responsibility to help the unit producer decide on techniques 
of pictorialization which will utilize the resources of the medium to 
the utmost. Experience has shown that a continuity should not be 
regarded as a final shooting script until the production department is 
ready to add its own approval to that of the research department. 

250 F. S. CELLIER Vol 48, No. 3 

Once the production script has been approved, it becomes the re- 
sponsibility of the production department to assist the unit producer 
in his advanced planning which includes costing, location or studio 
arrangements, casting, and scheduling. In the production stages of 
the film, the production department should make available to the 
unit producer, who is directing the picture, the best camera crews and 
studio facilities and other technical resources obtainable within the 

A classroom film is shot in much the same way as any other film, 
with perhaps two noteworthy exceptions. In the first place, a very 
great deal of the work has to be done on location. If one is making a 
film about the pygmies of Africa, one goes to Africa and shoots the 
pygmies there, and if one is making a film on the production of shoes, 
one goes to a shoe factory for the purpose. Since the nature of the 
classroom film calls for a scrupulous attention to detail and a pro- 
fusion of close-ups in which the camera stays on a process for many 
feet at a time, the location arrangements call for the utmost in tact 
and diplomacy. Nobody likes to have his factory disturbed by 
directors, assistant directors-, cameramen, assistant cameramen, 
electricians, and grips, not to mention dollies, cameras, lights, lengths 
of cable, and all other paraphernalia of motion picture making. This 
is especially true if, as in all authentic classroom films, the factory 
has no monetary interest in the film whatever. People on piece work 
in such a factory present an especially challenging problem to the 

Similarly, no scientist likes to have his laboratory routine broken 
up by film production, unless he is sure that the resulting film will 
make a definite contribution to education in his field of interest. 

The other way in which the production of a classroom film differs 
from that of, let us say, "Forever Amber", is that we cannot afford 
the luxury of spending $300,000 on a production and then calmly 
scrapping every foot we have shot and starting all over again. When 
you sell a classroom film at a given figure to a market of a given size, 
you stay within a budget or lose your shirt. And staying within 
a budget means, for example, that you rarely, if ever, even get to see 
your studio rushes before you strike your sets. The producer of 
classroom films just does not know what it means to be able to see 
the rushes of today's shooting tomorrow morning, and to decide to go 
back and do the whole thing over again if he does not quite like the 
angle at which someone's tie was hanging in a close-up. 


He shoots his scene once with as few takes as possible, and had 
better do it right, because that is the one and only time he will be 
able to afford the studio rental and the actors' fees and all the rest of 
the charges that go into even a single day's shooting. EBF recently 
completed a picture called "Public Opinion", for which much of the 
work was done in the studio. It is a fair example of the amount of 
careful planning and maximum utilization of the few precious hours 
which the budget allows for studio work. 

After the film is shot, the production department of a classroom film 
company should continue to make available to the unit producer the 
most competent technical assistance procurable. Film editors and 
cutters should be people who really know their job; and while the 
unit producer retains responsibility for the film to the end, he will 
do what Laurence Olivier did in the production of "Henry V", and 
regard his film edito'r as a major colleague. When the classroom film 
is finally edited and ready for scoring, it should be the responsibility 
of the unit producer to secure the final approval of the research de- 
partment and the subject matter collaborator, as well as the produc- 
tion department, before the narration is recorded. 

The Market. In thinking about the market for classroom films, 
companies in the field have to take a certain number of very hard 
facts into very careful consideration. To begin with, schools have 
limited budgets. I need hardly remind you that our schools are 
shockingly underfinanced. 

In the second place, school people are conservative. They are ac- 
customed to doing things in time-honored ways and they are espe- 
cially allergic to frills and furbelows. It has taken twenty years to 
persuade even a small proportion of school people that the film is a 
legitimate teaching tool. A very great deal of teacher-education re- 
mains to be done. 

But even those school people who are persuaded that the film is 
indeed a valid teaching instrument are still lamentably under-supplied 
with projectors. It is no exaggeration to say that of the schools which 
will be using films regularly ten years from now, only about ten or 
fifteen per cent have projectors available today. 

All this adds up to the fact that schools are "tough to sell". Pro- 
ducers of classroom films should never kid themselves that school 
people are easy meat for any smart salesman. They just cannot af- 
ford to be. That is the main reason why the product had better be 
good if it is ever going to sell good, not in terms of what the audience 

252 F. S. CELLIER 

in a neighborhood movie would call good or some of our long-haired 
friends would call good, but what practicing teachers on the every- 
day operational classroom level would call good. 

Most schools that use films have by now realized that it is far better 
to own the prints than to rent them. The very nature of the class- 
room film makes it necessary for the teacher to have it instantly avail- 
able at the precise moment when he needs it for the specific work in 
his class. No teacher is able to foresee months in advance that on a 
given Thursday morning at 10:30 A.M. he will require such-and-such 
a film. Yet, if he has to rely on a rental library, this is the type of 
decision he is required to make. In many of our better school sys- 
tems, this point is realized so thoroughly that libraries have been es- 
tablished for individual schools rather than for the city as a whole. 
The day may no longer be too far off when it will be as simple a 
matter for a teacher to get a film for immediate projection out of the 
school's film library as it is today to get a reference book for immediate 
use out of the school's book library. 

Already there are countries abroad that are using American made 
classroom films in large numbers. The Union of South Africa, for 
example, has been a customer of EBF for the past ten or twelve years, 
and has purchased many hundreds of both English and Afrikaans 
language prints of upwards of 150 subjects. One hundred twenty- 
five subjects have been translated by EBF alone into Spanish and up- 
wards of one hundred into Portuguese. Classroom films in these 
languages have been distributed in Latin America for a number of 
years. Other languages into which Encyclopaedia Britannica Films 
have been translated include, Dutch, Norwegian, Czech, French, 
Greek, Turkish, Arabic, and Chinese. 

Conclusion. There is one prediction that one can safely make in 
conclusion: The considerable success which the armed forces 
achieved during the war with training films has given millions of 
people an inkling of the teaching potentialities of this medium. 
Virginia will not be the only state to launch a visual education pro- 
gram with a substantial appropriation. What we are witnessing to- 
day is but the dawning of the classroom film era. 



Summary. A type of fully compensated constant resistance network is described 
which provides a larger family of equalization characteristics particularly suited to 
corrective use in rerecording as determined by aural monitoring. 

Constant-resistance networks have found widespread application 
to equalization problems encountered in the motion picture industry. 
Such networks are used in recording systems for original dialogue and 
musical recording, and to a far greater extent in the rerecording proc- 
ess. The use of such networks" has been discussed previously, and 
the design work undertaken has pointed to the desire for networks 
which afford a maximum degree of usefulness. 1 "" 4 

Generally, networks may be divided into two classes : those which 
have characteristics for specific application, such as dialogue equali- 
zation, film loss compensation, and modulator equalization; or those 
which are intended for corrective use (determined largely by aural 
monitoring of the material with the introduction of sufficient equaliza- 
tion to improve the sound quality or balance) or to provide other 
changes in quality to produce certain dramatic effects. 

In the field of compensation may be included the correction of de- 
fects caused by the acoustical conditions surrounding the point of 
pickup, variations in microphone pickup which may cause apparent 
variations in an actor's voice, or the interfering effects of wind, stage, 
or other unwanted noises. Correction for dramatic effects will 
usually require the ability to raise or lower certain discrete frequency 
bands in amplitude. These problems are not only encountered in 
sound recording on film, but in the fields of disk recording, radio 
broadcasting, and television. 

The choice of a particular type of network depends upon the re- 
quired insertion loss, the impedance of the circuit in which it is to 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** Electrical Research Products Division, Western Electric Company, Holly- 




Vol 48, No. 3 

operate, and the reaction of the network's impedance characteristic 
upon the frequency response of the equipment associated with it. 
The last factor is of considerable importance when a network is 
connected to the input circuit of an amplifier, since frequently the 
amplifier response is altered when working into an incorrect or varying 
impedance. A comparable condition may exist when a network is 
operated on the output of an amplifier, particularly if the amplifier 
output stage contains pentodes. In addition, if a number of net- 
works are to be connected in tandem, the constant-resistance struc- 
ture must be terminated ideally if terminal effects are to be made 



FIG. 1. Equalizer schematic. 

Several constant-resistance networks in tandem will add their 
respective loss characteristics without interaction, provided they are 
designed for the same nominal terminating resistance, and are actually 
terminated in this resistance at one end. If neither end is well ter- 
minated, or if some nonconstant resistance network is included in the 
chain, the over-all loss characteristic will show interaction effects. 
The generally desirable features of networks of this type have re- 
sulted in their nearly universal use for modifying response charac- 
teristics in sound recording processes. 

The type of'.constant resistance structure to be considered in this 
paper is included in the previously mentioned classification of cor- 
rective networks whose equalization characteristics in frequency and 
amplitude are primarily judged on the basis of aural monitoring of 


the material in question. This type of network has taken two 
general forms : (1) a resonant circuit providing a broadly tuned char- 
acteristic which may be either additive or subtractive in its effect; 
or (2} shelf -type characteristics effected through the use of compli- 
mentary sets of simple impedance elements; e. g., an inductance and 
condenser. Various tuning frequencies for the resonant sections may 
be selected to conform to individual desires. 

A specialized form of constant resistance structure which has de- 
sirable features will be described. A network of the type shown in 
Fig. 1 may be so designed that the half loss, i. e., one-half of the total 
equalization for any attenuator setting,- occurs at the same frequency. 
In this respect the network follows the same general design as that 
described by Miller and Kimball. 2 Such a network provides a family 
of equalization curves for various attenuator settings which do not 
overlap, provided the network is in series with a suitable compensat- 
ing attenuator section. This is necessary since the equalizer's in- 
sertion loss is not constant for the various steps of the attenuator af- 
fording the variable equalization. 

Since additive and subtractive conditions of equalization require 
different degrees of attenuation compensation, if the equalization is to 
occur plus and minus about a common reference, effectively three 
separate attenuators are required. One attenuator is associated with 
the impedance elements, and the other two provide the compensating 
functions. For purposes of convenience, in order to avoid the sepa- 
rate adjustment of three individual attenuators, the three attenuators 
may be ganged so that a common control will operate all three simul- 

Complementary equalization curves for additive and subtractive 
conditions utilizing the same impedance elements, except transposed, 
will occur only when the maximum equalization is 8.36 db. Since 
this is an odd figure, it appeared more convenient to choose 10 db as 
the maximum amount of equalization, and to accept the slight dis- 
crepancy in complementary characteristics so caused. The ad- 
vantage of transposing impedance elements for additive and sub- 
tractive conditions is obvious, since it halves the required number of 

The design requirements may then be summarized as follows : 

(1) The network should provide both additive and subtractive 
types of equalization, 



Vol 48, No. 3 



The degree of equalization about a reference should be =*= 10 

db, adjustable in 1-db steps. 

Compensation to offset variable insertion loss for different 

amounts of equalization should be included. 

Means should be provided to utilize only one set of impedance 

elements (tuned to the chosen frequency), with switching to 

transpose elements for the additive and subtractive conditions 


FIG. 2. Equalizer circuits. 

In addition, switching should be provided to utilize single in- 
verse elements of the series and parallel connected impedances 
in order to obtain the untuned or shelf -type characteristics. 
It would be desirable to employ a ganged attenuator so that 
automatic compensation for insertion losses will occur, and 
that the attenuator be so constructed that both additive and 
subtractive equalization will result from rotation of one dial. 

With such an equalizer, two methods of assembly may be provided. 
Considering the ganged attenuator and a switch for obtaining tuned 

March 1947 



and untuned conditions as a basic unit, various impedance element 
groups tuned to selected frequencies may be individually selected by 
means of an additional switch and be connected to the one attenuator. 
This provides the choice of many equalization characteristics, only 
one of which may be used at any one time. If the rerecording prac- 
tice requires use of several identical characteristics simultaneously, 
then the better method would appear to be to associate only one set of 
impedance elements with each attenuator, or to restrict the choice of 
various tuning frequencies to a smaller number. In any event, the 
flexibility of arrangement is great, and elements can be assembled to 
meet a variety of operating requirements. 




60 120 240 500 700 3000 6000 






FIG. 3. Control panel. 

An equalizer assembly embodying these principles is now de- 
scribed. A single attenuator providing the functions indicated in 
Fig. 1 is arranged so that rotation in either direction from a midpoint 
affords additive or subtr active equalization. The compensating at- 
tenuators are ganged with the equalizer portion of the attenuator so 
that a single knob controls the three functions. A simplified circuit 
schematic is shown in Fig. 2. Here the impedance elements are as- 
sociated with a switching key so that the resonant circuit elements 
may be connected respectively as : 

(1) Tuned resonant and antiresonant circuits, Lid and Z/ 2 G; 

(2) Untuned, using complimentary impedances L\C^ or imped- 
ances 1/2 Ci, to obtain shelf -type characteristics. 



Vol 48, No. 3 

As many keys and sets of impedance elements may be employed 
as desired. Normally, six to eight different tuning frequencies would 
appear to be adequate, and the frequencies might be chosen on an 
octave basis. All sets of keys and impedance elements connect to a 
frequency-selecting switch so that a choice of frequency may be made. 
The output of this switch connects to a transposing key which trans- 
poses the Zu and Z^i, impedance elements for the additive and sub- 
tractive conditions. This key is operated by a cam attached to the 
ganged attenuators. Thus, in operating the single-dial equalization 
control, the impedance elements are transposed automatically. Con- 
nections from this key then connect the generalized impedances to the 
attenuator. A possible form of control panel is shown in Fig. 3. 

Fig. 4 shows the maximum 
equalization curves for additive 
and subtractive conditions for 
one frequency for the tuned 
characteristics and the two types 
of 'shelf characteristic. The 
nominal insertion loss of the net- 
work for no equalization, i. e., 
flat transmission, is 10 db. All 
equalization takes place 10 db 
in 1-db steps about the base line 
(10-db insertion loss). 
This type of equalizer has many uses and is sufficiently flexible in 
design to be used in a variety of ways, as indicated. It is compen- 
sated for varying insertion loss so that the family of curves do not 
overlap and equalization occurs plus or minus about a reference base. 
The various types of equalization provided, i. e., the tuned and shelf - 
type characteristics, are particularly adapted to corrective work 
undertaken on the basis of aural monitoring. 


1 HOPPER, F. L.: "Electrical Networks for Sound Recording", /. Soc. Mot. 
Pict. Eng., XXXI, 5 (Nov. 1938), p. 443. 

2 MILLER, WESLEY C., AND KIMBALL, HARRY R.: "A Rerecording Console, 
Associated Circuits, and Constant B Equalizers", /. Soc. Mot. Pict. Eng., XLIV, 
1 (Sept. 1944), p. 187. 

3 THAYER, W. L.: "A Multisection Rerecording Equalizer", /. Soc. Mot. 
Pict. Eng., 45, 5 (Nov. 1945), p. 333. 

4 GRIGNON, L. D.: "A Three-Band Variable Equalizer", /. Soc. Mot. Pict. 
Eng.. 46, 1 (Jan. 1946), p. 64 . 

FIG. 4. Characteristics. 



Referring to Fig. 1, for the condition of maximum equalization R 2 = zero, and 
Ri = infinity: The remaining resistance elements RiRo, RQ, and R^ form a con- 
ventional bridged-7" type pad. It has been shown 1 that the resistance values for 
the bridged -T type pad may be computed from the equation 

Z n = R(ea - 1) (1) 

where Z\\ corresponds to R\, and a is 0.23 times the insertion loss of the pad in db. 
The value of R 3 may be determined from the relationship 

Ri X R 3 = # 2 o (2} 

The maximum insertion loss of the complete equalizer is given by 
Maximum insertion loss db = 

\/Equalization step db X Maximum equalization db. (3) 

For an attenuator having a maximum loss of 10 db, the insertion losses for 
various steps of equalization are as follows: 

Equalizer Insertion 

Step in db Loss db 


2 \2 X 10 4.47 

3 5.48 

4 6.32 

5 7.07 

6 7.74 

7 8.36 

8 8.94 

9 9.48 

10 VlO X 10 10.00 

As an example, consider a network having a maximum insertion loss of 10 db. 
The equalization by (5) for this condition is also 10 db. RI by Eq (1) for a 600- 
ohm circuit is 

Ri = 600(e- 115 X 10 - 1) = 1295 ohms 

RZ from Eq (2} is 

1295 #3 = 600 2 R 3 = 278 ohms 

For say, 5 db of equalization, the insertion loss is 7.07 db, from Eq (1) 

Ri = 600(e - ll5 X 7 - 07 - 1) = 753 ohms 

753 X R s = 600 2 R, = 478 

Ri for the 5-db equalization condition may be computed as follows : 
Let R p be the parallel resistance of RI and RZ 

R p = R ( e - 1) (4) 

The loss a represents in this case the difference between the insertion loss and 
the equalization, or 7.07 - 5 = 2.07 db and R p = 600(e- 116 X 2 - 07 - 1) = 161 

260 F. L. HOPPER 

ohms. RI previously computed for the 5-db equalization condition was 753 ohms; 

Rz 75 - 161 and R 2 = 205 ohms 

#2 + 750 
R 2 and R 4 are complementary; hence 

R 2 X #4 = #o 2 or 205# 4 = 600 2 
#4 = 1755 ohms 

The values of Zn and Z 2 i may be computed in the manner outlined, 1 together 
with the insertion-loss characteristics for the maximum attenuator loss, 10 db, 
which is also equivalent to the maximum equalization. 


MR. R. WILSON: All of these equalizers are designed to distort frequency char- 
acteristics, but do they add any other form of distortion because of phase shift? 

MR. HOPPER: So far as I know the constant resistance network has very little 
phase shift. We have made extensive tests in the past in which a large amount 
of phase shift was introduced to see whether it had a great deal of effect on quality. 
I do not believe anyone was ever able to observe that it did. The constant re- 
sistance network provides a volume distortion, it is true, because it alters the dis- 
tribution and amplitude of the components. But aside from that form of distor- 
tion, I do not believe there is anything else. 

MR. JOHN HAWKINS: Has anyone made a survey of the various rerecording 
equalizers used in sound picture recording? 

MR. HOPPER: I can speak only generally about these types of shelf and tuning 
characteristics used in Western Electric equipment. Networks of this or similar 
types are used by MGM, Fox, and Paramount for corrective equalization. There 
seems to be more discrepancy in the filter or equalizer used to simulate some par- 
ticular source of sound, such as a radio or telephone. 

MR. F. J. GRIGNON: I would like to say one thing here about the possibility of 
using the tuning frequencies spaced in octaves. Experience would seem to indi- 
cate that at the higher frequencies it is better to reduce the interval, rather than 
jump from 3000 to 6000 cycles, for example. 


Summary. It is generally conceded that the present 5 /i&-in. diameter shaft and 
l /%-in. drive key on present film reel handling equipment such as magazines, rewinds, 
etc., are inadequate to support and drive 2000-ft reels of 35-mmfilm. Much unneces- 
sary film damage is caused by the reel wobble, backlash, and poor alignment caused 
by this situation. This paper describes an improved reel design featuring a 1-in. 
diameter splined hub shaft opening and an automatic ball and groove locking device 
to provide accurate lateral alignment and eliminate manually operated keys on reel 

To reduce film shipping damage, a design is suggested for an exchange reel shipping 
case with a center shaft passing through the 1-in. openings in the hubs of the new reels. 

Introduction. The technical literature of this industry contains 
numerous references to the early days of motion picture projection 
when it was customary to run the projected film off into a barrel or 
sack, later to be rewound onto the shipping reels. This practice was 
occasioned at least partly by the fact that the early projectors were 
manually driven; the load imposed by a slipping take-up clutch 
would have been an additional burden on the operator who was al- 
ready as busy as the proverbial .paper hanger. With the advent of 
motor drives for projectors, this situation changed. It became prac- 
tical to wind the projected film directly on reels as it came from the 
projector. It was natural to use for this purpose reels of generally 
the same size and construction as those used for handling and ship- 
ping the film; and as a matter of fact, larger reels were prohibited 
in many localities by the fire hazards resulting from poor construc- 
tion of magazines and of film handling and storage containers. 

As fire hazards were reduced by improved projector, magazine, and 
container designs, the restrictions on reel size were gradually relaxed. 
Reels capable of holding approximately 2000 ft of film came into use 
and, for a time, 3000-ft reels were used to some extent. The 3000-ft 
reels eventually were found to be impractical, partly because of the 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** Detail Production Company, Detroit, Mich. 




Vol 48, No. 3 

increased fire hazard, partly because they were excessively heavy to 
handle, and to a large extent, because the shafts and drive keys of ex- 
isting film handling equipment were entirely inadequate in size and 
strength to operate such reels without very rapid wear. 

It is generally conceded that the 5 /ie-in. diameter shaft and l / s - 
in. drive key on present film reel handling equipment such as maga- 
zines, rewinds, etc., are inadequate to support and drive even 2000- 
ft reels of 35-mm film. They are a hangover, so to speak, from the 
days of 1000-f t reels ; and they directly and indirectly cost the indus- 
try many thousands of dollars every year in lost show time, ruined 

projection equipment, and 
heavy film damage. The 
overloaded shafts wear loose 
in their bearings and wear 
out the shaft holes in projec- 
tion reels to cause dangerous 
reel wobble and serious mis- 
alignment. The undersized 
drive keys wear thin or break 
and chew out the keyways in 
reel hubs to cause backlash 
between the take-up shaft and 
the driven reel. This backlash 
may become so great that the 
reel goes into rotation with a 
heavy jerk when the machine 
is started, thus pulling out 
film sprocket holes or actually ripping the film apart. 

The turnover latches at the ends of present reel shafts are other 
offenders. They are relatively ineffective at anchoring the reels to the 
shafts in good alignment and in even the best designs, spring breakage 
and hinge failures are common, simply because the shaft diameter is 
too small to permit construction of sufficient strength to withstand 
heavy-duty service. 

Design and Construction. The projection reel which is the sub- 
ject of this paper, and which is now being marketed under the trade 
name of "MiUereel", was designed to overcome immediately some of 
these imperfections and to permit the eventual use of more adequate 
shaft dimensions in newly designed film handling equipment. This 
reel is shown in Fig. 1. Its outstanding design features are the 1-in. 

FIG. 1. 

Complete Millereel, showing 
adapter in place. 



diameter shaft opening in the hub having ten longitudinal splines to 
engage similar splines on the mounting shaft, and an internal spring- 
tensioned detent ball to engage a turned locking and center groove in 
the shaft to align the reel positively on the shaft laterally and to pro- 
vide for automatically locking it in the correct position. The ten 
intersecting spline sections in the reel hub and on the shaft provide 
means for transferring the torque at the shaft to the reel with virtually 
no lost motion and with the loading spread over such a large area of 
contacting surfaces that the chance for wear on the surfaces is reduced 
almost to the vanishing point. The shaft and the reel hub, in effect, 

FIG. 2. Component parts of Millereel hub assembly and shaft. 

become one piece of metal when the reel locks into place, for during 
manufacture, the hubs and shafts are held to dimensional tolerances 
sufficiently close to produce a maximum clearance of two-thousandths 
of an inch, which is entirely adequate to permit the reels to be easily 
put in place and removed from the shaft but allows no perceptible 
play in any direction after the detent ball drops into the centering 
and locking groove. 

Details of the hub and locking device construction are shown in 
Fig. 2. The detent ball and spring operate in the tube which may be 
seen next to the reel in the figure. The rear end of this tube is 
pinched shut and then is milled to a semicircular contour to bear 
against one of the spacers between the two halves of the reel. The op- 
posite end enters the counterbored hole visible in the splined hub for 



Vol 48, Xo. 3 

the reel; the steel detent ball protrudes through a smaller hole be- 
tween one pair of splines to engage the locking and centering groove 
of the shaft. The spline ends on the shaft are tapered and their cor- 
ners are bevelled to guide the hub splines smoothly into engagement 
with the shaft splines as the reel is placed in position. It is obvious 
that the engagement may be made in any one of ten different angular 
positions of the reel with respect to the shaft, thus permitting the reel 
to be put into position with a film slot upward without the necessity 
for the usual spinning operations to align key slot and key, and to 
bring a film slot to the preferred threading position. This apparently 

minor matter is actually a con- 
siderable operating convenience. 
A still greater convenience, 
and one which contributes to 
increased safety in operation, 
derives from the fact that the 
reel is automatically locked to 
the shaft by the detent action 
as it is pushed into position. 
There is no manually operated 
reel lock to be overlooked with 
possible disastrous results dur- 
ing the running of the reel, and 
the hand operation of turning 
the reel lock is eliminated. 
Correct lateral positioning of 
the reel on the shaft is assured 
and the spring action of the 
detent mechanism permanently eliminates lateral end play between 
reel and shaft. Such end play is often the cause of severe film damage, 
since it may disturb alignment sufficiently to pull the film off the 
soundhead's holdback sprocket or pull patches apart because of in- 
terference between the reel flanges and the edges of the moving film. 
The new reel is constructed of two identical half sections which are 
aligned and are firmly locked together by compound spacer members 
within the film hub center section of the reel. The matching faces of 
the film hubs and of the three internal spacer bosses are accurately 
machined to a height which will give the required 1.58-in. width at 
the hub's film bearing surface. The bosses are bored out to take tubu- 
lar, tapped inserts which are somewhat shorter than the over-all reel 

FIG. 3. Millereel (adapter removed) 
showing new-style shaft in place. 


thickness. Flat-head Phillips screws seating in the reel halves and 
entering the tubular inserts draw the two sections of the reel tightly 
together, with the inserts providing the necessary alignment action. 

The reel half sections are fabricated from lightweight but strong 
cast aluminum alloy. All edges are smoothly rounded to protect 
both the film and the projectionist's hands. The hub sections have 
six 7 /s-in. diameter finger holes equally spaced on a radius which per- 
mits them to be used not only for handling the reel but also as anchor 
points for use in disengaging the reel from the splined shaft hub. The 
hub splines terminate about J /4 in. from the outer end of the hub, 
leaving thus a plain hub extension of this length to serve as a release 
"button". Two fingers anchored in the holes, with the thumb press- 
ing on the shaft hub, apply the necessary force to disengage the detent 
ball from the center and locking groove and thus release the reel from 
the shaft hub. The action is easy, straightforward, and natural, and 
it is much more rapidly done than the more complex one of. lifting a 
turnover locking device and then grasping the reel for removal. 

The diameter of the reel's film hub is 5 in. and the flanges are 15 
in. in diameter, giving a film capacity of 2070 ft. At a film speed of 
90 ft per min., the reel thus allows for a run of 23 min. The film hub 
is provided with three equally spaced Vie-in, milled lateral film anchor- 
ing slots. 

An obvious, though important, advantage in having the reel con- 
sist of two identical half sections lies in the fact that accidental dam- 
age to one flange does not necessitate complete replacement of the 
entire reel. As was mentioned in the discussion of the splined shaft 
and hub design, manufacturing tolerances on all matching compo- 
nents are being held to the small values required to permit ready field 
interchangeability of all reel parts without hand fitting. The over-all 
design and construction are of such ruggedness as to withstand easily 
the rough handling projection reels frequently get, but in the event 
of actual damage, the broken part may be replaced with little effort 
and at moderate cost. 

Adapters. It is almost axiomatic in this industry that improved 
equipment designs and new processes, to be successful, must be 
capable of being used with existing associated equipment items or in 
combination with existing processes, at least during a transition 
period of more or less extended duration. This is partly because of 
the psychological difficulty involved in getting the industry to agree 
about anything, and partly because of the physical impossibility of 

266 E. S. MILLER Vol 48. No. 3 

getting the whole motion picture "plant" equipped with anything 
new overnight. 

With this thought in mind, the new reel design has been provided 
with an adapter to permit the reels to be used on existing film han- 
dling equipment without the need for changing it in any manner. 
Other adapters consist of replacement shafts for various film handling 
equipment items, such as specific makes of magazines and rewinds. 
Such shafts are obviously limited in diameter to the dimension which 
will enter the bearings of the apparatus in which they are to be used, 
but they do carry the splined shaft hub which permits many of the 
advantages of the new reel design to be secured at once. 

The adapter which makes the new reel directly interchangeable 
with older designs is shown in Fig. 2 directly to the right of the in- 
ternally splined reel hub. It is a cylindrical machined piece having 
external splines to mate with those of the hub, a turned locking and 
centering groove, and a center bore with duplex keyways to fit the 
5 /ie-in. shafts and Ys-m. keys of existing film handling equipment. 
By use of these adapters, a theater may gradually replace older reels 
with those of the improved design until such time as a complete work- 
ing set of the new reels is on hand, at which time the shafts of the exist- 
ing film handling equipment may be replaced, or the equipment it- 
self may be replaced with new units having adequate-sized shafts. 
A replacement shaft for Simplex upper magazines is shown in Fig. 2 
next to the other items. 

Fig. 3 is another view of the reel, showing it partially in place on the 
splined shaft end. This view also shows clearly the flange and film 
hub design and illustrates how corners and edges likely to touch either 
the film or the projectionist's hands have been rounded off to make the 
reel exceptionally safe to use. 

Reel Shipping Containers. Probably the roughest handling film 
gets takes place as it journeys between exchanges and theaters. 
Present practice has the reels of film squeezed side by side into closely 
fitting metal containers for these trips. The only support for the 
loaded reels comes from the container walls via the reel flanges and 
via their stacked hubs. It is no wonder, therefore, that both the reels 
and the film are frequently damaged, for the more or less rigid hubs 
in close contact cannot entirely prevent the necessarily somewhat 
flexible flanges from bending enough to transmit large forces to ad- 
jacent reels and hence to the film edges. Furthermore, the flanges 
cannot practically be made rugged enough always to withstand the 


heavy radial stresses which occur when containers are accidentally 

The one-inch diameter shaft opening in the new reel design makes 
possible the construction of a shipping case for loaded film reels which 
would almost completely eliminate the kind of reel and film damage 
just outlined. The case will have a central supporting shaft passing 
through the reel hub shaft openings to support the reels within the 
case with about 1 /2-in. clearance between the walls and the reel flange 
edges. In this manner, the flanges would be protected against all 
radial strain and by the use of semiresilient spacers between adjacent 
hubs, they could likewise be protected against strains which would 
otherwise be transmitted ' from one flange to another. With the 
necessity for jamming the reels tightly into the container eliminated, 
the present expensive and inadequately strong split construction 
could be abandoned in favor of much simpler and more rugged cov- 
ered metal boxes. Much handling time would be saved in addition 
to the savings produced by lessened film and reel damage. Nearly 
everyone who has had occasion to handle film at one time or another 
has encountered reels so tightly stuck in their containers that almost 
heroic measures were needed to get them out for use. All too fre- 
quently such measures ruin the container or the reel, and sometimes 
also damage the film. 

A film reel shipping container for the new reels along the lines just 
discussed is now being designed and should shortly reach the equip- 
ment market. Design models are being tested thoroughly under the 
most adverse possible conditions, and it is felt that the ultimate pro- 
duction models will represent a completely satisfactory solution to the 
problem of how to protect loaded film reels adequately in transit. 

Reels for Other Film Sizes. While the new reel design is cur- 
rently being manufactured in only the 2000-ft size for 35-mm film, 
its advantages become of even greater importance when the problems 
involved in the handling of the proposed wider films are considered. 
The positive drive, and automatic centering and locking features of 
the new design would be of extreme usefulness, and the shafts in film 
handling equipment could be made fully adequate in diameter to sup- 
port the increased weight of the wider film. 

There is a need now, and it is planned to meet this need soon, for 
improved 16-mm film reels of large diameter to carry the longer shows. 
In many respects, the driving problem is even more severe than it is 
in the case of reels for the wider films, for the 16-mm reels cannot 

268 E. S. MILLER 

have nearly the same bearing contact with the shafts even though 
their outside diameters may be greater than those of reels for the 
wider films. The splined shaft and hub construction offers an ex- 
cellent solution to this problem ; and, of course, the other advantages 
of the new design are equally beneficial. 

Conclusion. It is hoped that this outline of the principal fea- 
tures of the improved reel design will serve to call its merits to the 
attention of those responsible for the design of other equipment items 
involved in the handling of film. The returns to the designer and 
manufacturer in this instance are far overshadowed by the possible 
benefits to the industry resulting from improved performances and 
reduced damage to films. 



The editors present for convenient reference a list of articles dealing with subjects 
cognate to motion picture engineering published in a number of selected journals. 
Photostatic or microfilm copies of articles in magazines that are available may be 
obtained from The Library of Congress, Washington, D. C., or from the New York 
Public Library, New York, N. Y., at prevailing rates. 

American Cinematographer 

27, 12 (Dec. 1946) 

The M-R A New Super High-Intensity Carbon Arc 
Lamp (p. 438) 

28, 1 (Jan. 1947) 

Fastax High Speed Camera (p. 7) 
Staging Musical Routines for Camera (p. 8) 
Development of the Cinematographic Art (p. 10) 

28, 2 (Feb. 1947) 

Recent Developments in Photographic Optics (p. 44) 
Photographic Highlights of 1946 (p. 46) 
Mood in the Motion Picture (p. 48) 
Ansco's New Film for Use in Color Motion Picture 
Production (p. 65) 





British Kinematograph Society, Journal 

9, 4 (Oct.-Dec. 1946) 
Future of the Sub-Standard Film: 

1. In Commerce (p. 122) 

2. In Education (p. 124) 

3. In Scientific Research (p. 126) 
Basic Principles of Sound for 16-Mm: 

1. Acoustic Aspects (p. 130) 

2. Film Recording (p. 131) 
Demonstration of New Equipment: 

Rapid Film Processing Tank (p. 135) 

Shutter Timer (p. 136) 

Exposure Timer (p. 138) 

An Almost Distortionless Amplifier (p. 139) 

An Indicating Color Comparator (p. 140) 

Ideal Kinema 

13, 138 (Jan. 1947) 

Technical Progress in the First Year of Peace- 
Further Developments Which Lie Ahead (p. 25) 









Vol 48, No. 3 

British Contributions to Kinematograph Technique 
A Newman Memorial Lecture (p. 28) R. H. CRICKS 

An Australian- Designed Arc Lamp Feature of the 
Latest Model "Tru-Trim" (p. 33) 

International Photographer 

18, 11 (Dec. 1946) 

History of Bi-Pack Photography (p. 5) 
The Art Reeves Camera (p. 6) 
Improvement for Process Department (p. 7) 
Largest Outdoor Screen (p. 18) 

The Mitchell "16" (p. 20) 

High-Speed 16-Mm Developing Introduced by 
Chroma-Tech Lab. (p. 22) 

19, 1 (Jan. 1947) 
Lumenized Lenses (p. 6) 

Studio Technique in Television (p. 18) 

International Projectionist 

21, 12 (Dec. 1946) 
Bubbles in Lenses (p. 9) 

The New Motiograph AA Projector (p. 12) 
A Six-Phase, Full- Wave Rectifier (p. 16) 

22, 1 (Jan. 1947) 
Magnetic Recording (p. 7) 

What Color-Correction Means (p. 10) 
Incandescent Lamps for Film Projection (p. 14) 
The Trivision Three-Dimensional Process (p. 17) 

Photographic Society of America, Journal 

13, 1 (Jan. 1947) 

The Relative Corrosion Effect on Stainless Steels of 
Rapid Fixing Baths Containing Ammonium Chlo- 
ride and Ammonium Sulfate (p. 30) 

RCA Review 

7, 4 (Dec. 1946) 

Simultaneous All- Electronic Color Television (p. 459) 

Frequency Modulation Distortion Caused by Com- 
mon- and Adjacent-Channel Interference (p. 522) 

Recording Studio (p. 634) 

Television A Bibliography of Technical Papers by 
RCA Authors 1929-1946 (p. 641) 

Radio News 

37, 2 (Feb. 1947) 

All-Electronic Color Television (p. 7) 
The Reproduction of Disc Recordings (p. 13) 















Some Possibilities in Stereophonic Broadcasting 

(p. 18) H. E. ENNES 


6, 2 (Feb. 1947) 
Design of Recording Studios for Speech and Music G. M. NIXON AND J. 

(p. 37) VOLKMANN 

Thomascolor for Television (p. 66) 



James Y. Dunbar, acoustic engineer for Johns-Man ville Sales Corporation, 
New York, presented a discussion on "Space Acoustics for Recorded and Re- 
produced Sound" before the Atlantic Coast Section of the Society at its February 
19 meeting. Mr. Dunbar discussed the basic principles of acoustics, outlining his 
ideas as to how acoustics developed through the ages as vocal and musical presen- 
tations were increasingly presented in enclosed spaces. 

Mr. Dunbar also outlined specific applications to motion picture theaters, 
broadcast, recording, and television studios. He described some of the latest ap- 
plications of materials now in use and various types of treatment that have proved 
to be most suitable. 

In the discussion period which followed Mr. Dunbar's talk a great many ques- 
tions were asked by Section members and guests indicating a wide interest in the 
subject of acoustics. About 200 attended the meeting, held at the Hotel Penn- 
sylvania, N^w York. 


Malcolm G. Townsley, chief research engineer of Bell and Howell Company, 
Chicago, discussed aspects of his paper, "Auto-Collimator for Precise Measure- 
ment of Flange Focal Distance of Photographic Lenses", which was recently pub- 
lished in the Journal of the Optical Society of America, at the February 13 meeting 
of the Midwest Section in Chicago. Mr. Townsley explained details of the system 
relating to camera testing. It was pointed out that this system gives twice the 
accuracy of reading the focal plane position compared with any other method, 
such as the telescope or microscope test. An explanation was given of the method 
of determining the film position during running of the film. The instrument was 
demonstrated by Mr. Townsley following the meeting. 

The second speaker was Paul C. Foote, also of Bell and Howell, who gave a dis- 
cussion on "Modern Slide Projector Design". The problems of general optical 
design, including filament size, reflector position, heat filters, and slide tempera- 
ture, were described in detail and their application to the two new Bell and Howell 
2 X 2-in. slide projectors were discussed. The 300-watt projector was presented 
as a relatively long design of condenser system, allowing natural draft cooling. 


The 750- and 1000-watt projector uses a close-coupled condensing system and 
down-draft cooling over the base-up lamp enabling fresh air intake over the slide. 
The larger projector was used for the slides during the talk, and was demon- 
strated after the meeting. 

An inspection of the Lincoln wood plant of Bell and Ho well was conducted for 
the Section members and guests, under the direction of C. E. Phillimore. 


The Midwest Section of the Society has become affiliated with the Chicago 
Technical Societies Council, organized to promote general engineering activities 
and to publicize meetings held by technical societies in Chicago. Membership 
in the Council is held by 46 national and local technical groups, and their various 
activities are announced in Sci-En-Tech News published monthly by the Council. 


The Pacific Coast Section of the Society, at its meeting on Feb. 11, 1947, heard 
a paper on "Spectrophotometry" by Dr. Arnold O. Beckman and Robert Moulton 
of the National Technical Laboratories, South Pasadena, Calif. Mr. Moulton, 
who read the paper, described a quartz photoelectric spectrophotometer and 
explained its application to the color analysis of solids, liquids, and gases by both 
transmission and reflection. Although this instrument was not specifically de- 
signed for motion picture work, some ideas on its application were presented. 

During the discussion period, which was led by Dr. Beckman, Allen Gundel- 
finger of Cinecolor explained some of the specific applications in his laboratory for 
an instrument of this type. 

A 16-mm motion picture in color devoted to the general subject of color analysis, 
shown through the courtesy of General Electric Company, dealt with the use of a 
spectrophotometer in this field. 

About 130 members and guests attended the meeting, held in the review room 
of Western Electric Company, Hollywood. 


A new American Standard covering 163 letter symbols designed to give chem- 
ists and chemical engineers a uniform system of "shorthand" for use in their 
mathematical calculations has been completed and is now ready for distribution. 

The new group of symbols is designed to provide the chemist and the chemical 
engineer with an agreed group of letter symbols which will permit a new degree of 
uniformity in writing and discussion of chemical problems, particularly in text- 
books, scientific papers, lectures, and the like. 

The symbols covered in the new work, which is part of a much larger American 
Standards Association project in the whole field of letter and graphical symbols 
already agreed on or under development, are defined as follows in the standard: 

"A letter symbol is a single character, with subscript or superscript, if required, 
used to designate a physical magnitude in mathematical equations and ex- 


The symbols included in the present standard cover only the field thus defined 
and are not to be confused with those designating chemical elements or groups. 

In addition to a section covering 83 such general concepts as acceleration, 
diffusity, entropy, molecular weight, surface tension, thermal conductivity and 
others, the new standard has special sections dealing with terms relating to heat 
transmission, flow of fluids, evaporation, humidification, dehumidification, gas 
absorption and extraction, distillation, drying, sedimentation, filtration, screening 
and sampling, crystallization, centrifiigation, and also various dimensionless num- 
bers used by chemists. 

The new standard, designated as Z10.12, was developed under a representative 
committee of which J. H. Perry, technical investigator, development department, 
E. I. du Pont de Nemours, was chairman, and it is available from the American 
Standards Association, 70 East 45th Street, New York 17, N. Y., at 50 cents per 


A Committee on Nominations has been appointed by President Ryder, in ac- 
cordance with By-Law VII of the Constitution and By-Laws, to recommend 
nominations for offices expiring December 31, 1947. General elections are held 
prior to the October convention; offices expiring and incumbents are given 
on the reverse of the contents page of this issue of the JOURNAL. 

Voting members of the Society (Honorary, Fellow, and Active) are invited to 
submit recommendations for candidates to the Nominating Committee, sending 
names to the Chairman, E. A. Williford, 230 Park Ave., New York 17, N. Y., 
or to members of the committee as follows: Emery Huse, E. I. Sponable, H. W. 
Mo'yse, J. W. Boyle, E. W. Kellogg, K. F. Morgan, J. K. Milliard, and M. G. 
Townsley, whose addresses are given in the last Membership Directory. 

Only Honorary, Fellow, and Active members may hold office. A report of the 
Nominating Committee will be submitted to the Board of Governors at the July 
1947 meeting. 



Film Editor, 20 years' experience in newsreel and educational film pro- 
duction, and dubbing work, both 35-mm and 16-mm. Desires connec- 
tion with motion picture organization. Member Film Editors' Union 
Local 771. Write Louis L. Hess, 174 East 96th St., New York 28, N. Y. 

RanUaye, ZcUfoi of ike, Motion Picture ctt&iald, 

fTAe Technique of Motion Picture Production is the 
first unified presentation of modern technical practices 
in motion picture production . . . Compact and com- 
plete ... In plain terms that any interested layman can 
understand. . . 

("This volume is indicated on the desk of anybody who 
wants to know about the motion picture and how it is 











Technology in the Art of Producing Motion Pictures 

Leon S. Becker 

Cinematography in the Hollywood Studios : 

Black and White Cinematography John W. Boyle 

Putting Clouds into Exterior Scenes Charles G. Clarke 

Technicolor Cinematography Winton Hoch 

Special Photographic Effects Fred M. Sersen 

Re-Recording Sound Motion Pictures L. T. Goldsmith 

The Technique of Production Sound Recording . . Homer G. Tasker 

Prescoring and Scoring Bernard B. Brown 

Illumination in Motion Picture Production 

R. G. Linderman, C. W. Handley and A. Rodgers 

The Paramount Transparency Process Projection Equipment 

Farciot Edouart 

Motion Picture Laboratory Practices James R. Wilkinson 

The Cutting and Editing of Motion Pictures . . Frederick Y. Smith 
The Projection of Motion Pictures Herbert A. Starke 

Price $4.50* 

Each section written by a specialist in the motion picture industry. . . Authentic infor- 
mation on various technical problems of motion picture production. ... A useful and 
valuable reference for technicians, students, librarians, and others desiring techno- 
logical data on the motion picture industry compiled in one volume. 

Published for the Society of Motion Picture Engineers by Interscience Publishers, Inc., 
215 Fourth Avenue, New York 3, N. Y. 

* 20% discount to members in good standing if ordered through SMPE. Orders must be accompanied 
by check or money order, and include 2% sales tax if delivered in New York City. 


Vol 48 APRIL 1947 No. 4 



Historical Development of Sound Films, Pt. 1-2 


Report of the SMPE Committee on Progress 

W. V. WOLFE 304 

Some Special Problems of Post-Synchronization Mixing 


The Concentrated- Arc Lamp as a Source of Modulated 


A New Blooping Device G. LEWIN 343 

Improved Engineering Designs for Stage Doors, Trans- 
parency Screens, and Water Tank Bulkheads 

A. C. ZOULIS 348 

Electronic Fire and Gas Light Effect H. NYE 353 

Officers and Governors of the Society 361 

Committees of the Society 365 

Constitution and By-Laws of the Society 372 

Journal Award and Progress Medal Award 384 

Membership and Subscription Report 387 

Report of the Treasurer 388 

Society Announcements 390 

Copyrighted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 










** President: LOREN L. RYDER, 

5451 Marathon St., Hollywood 38. 
** Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
**Executive V ice-President: EARL I. SPONABLE, 

460 West 54th St., New York 19. 
""Engineering Vice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial Vice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
""Financial Vice-President: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
^Treasurer: E. A. BERTRAM, 
850 Tenth Ave., New York 19. 

**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 5451 Marathon St., Hollywood 38. 
*fjAMES FRANK, JR., 356 West 44th St., New York 18. 

"JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*JA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
*WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

*Term expires December 31, 1947. tChairman, Atlantic Coast Section. 
**Term expires December 31. 1948. TChairman, Midwest Section. 
"Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 

their annual membership dues; single copies, $1.25. Order from the Society at address above. 

A discount of ten per cent is allowed to accredited agencies on orders for subscriptions 

and single copies. 
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 

General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 

Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., 

under the Act of March 3, 1879. 


Vol 48 APRIL 1947 No. 4 



In this introduction I should like to set down the purpose of this 
paper, to say something about the way in which I propose to treat 
the subject matter contained therein, and perhaps even to make a few 
personal remarks. 

First, the purpose. There have been various documents published 
relating to the history of sound recording on film, but they have not 
been complete, nor have they, in most instances, attempted to rate 
the relative value of the contribution made by the various inventors. 
Since I am somewhat in the same position as the famous chemist 
Berthelot, who was declared to have been the last one who would know 
the whole of chemistry, I propose to undertake to arrange the tech- 
nical contributions leading up to the commercialization of sound mo- 
tion pictures in chronological order, and to attempt this evaluation. 
Perhaps I may be forgiven for this apparently egotistical point of view, 
because I was fortunate to have participated in bringing about the 
commercial development of sound motion pictures; and for at least 
a short period of time I was probably the only individual who had 
heard practically every sound record and knew intimately those en- 
gaged in making them. Late in 1926 I was, like Berthelot, overcome 
by a feeling of helpless futility; it was then that the art began such 
rapid expansion that I could no longer keep up with the tremen- 
dously increased number of sound records. 

In dealing with this development, I shall more particularly restrict 
my remarks to the photographic methods of sound recording and shall 
list in considerable detail the steps taken in the development of the 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** Twentieth Century-Fox Film Corporation, New York. 


276 E. I. SPONABLE Vol 48, No. 4 

Fox-Case system. The section of this paper which deals with the 
work of Theodore W. Case contains abstracts from correspondence 
which he kindly made available to me, and from the notes of the Case 
Research Laboratory, which he organized shortly after I joined him 
in 1916; I therefore know, of my own knowledge, that these notes 
were kept with a high degree of accuracy and detail, and are correct. 
I have quoted directly from these records in some instances, since 
they are available to the future historian the original Case Labora- 
tories having been made a museum in the city of Auburn, New York 
(now known as the Cayuga Museum of History and Art) . 

The remaining parts of the paper, dealing with the work of others, 
may have been treated in somewhat less detail : first, because much 
has already been written regarding their work and it seems unneces- 
sary to repeat it here (except to the extent required for a clear chrono- 
logical development of the subject), and, second, because I was more 
directly and intimately concerned with the work of Mr. Case. 

To the uninitiated, this account may prove dry reading at best; 
it is intended to do no more than appeal to those having a substantial 
interest in, and present knowledge of, the art. If it enables those now 
devoting their time and energy to the perfection of sound pictures to 
see something of the stages by which we arrived at our present state, 
it will have served its purpose. 


1857: Leon Scott patented in France what seems to be the 
first method of recording sound. 1 This disclosure shows the use of a 
stylus connected to a membrane through a series of levers and a 
method of tracing figures corresponding to speech, song, etc. on paper 
covered with lampblack. The paper was attached to a cylindrical 
drum, which could be rotated by hand and moved forward by a screw. 
He called the instrument the "phonautograph". 

1862: Another example of early interest concerning the nature 
of sound is found in the work of one Doctor Jan N. Czermak of 
Vienna, who succeeded in photographing the vocal chords in action. 2 

1877: Thomas Edison brought out his epoch-making invention, 
the first phonograph. It was similar in principle to the phonauto- 
graph but differed in that he used tinfoil on the cylinder and had 
his stylus attached directly to the vibrating diaphragm. In his 
later models, wax was used as the recording medium. 

1878: Professor E. W. Blake, of Brown Uniyersity, published a 


paper on "A Method of Recording Articulate Sounds by Means of 
Photography". 3 This describes a mirror actuated by a microphone 
and the moving of a beam of light over a photographic plate. 

1880: A. G. Bell patented the method of using selenium for 
detecting sound signals sent over a modulated light beam. 4 The ex- 
periments in light telephony leading up to this patent were carried on 
in 1879. 

1880: Charles E. Fritts filed a patent application in the United 
States entitled "Recording and Reproduction of Pulsations or 
Variations in Sounds and other Phenomena". 5 This application is 
remarkable in its completeness, broad scope, and length of time in the 
patent office. As finally granted, on Oct. 31, 1916, it covered 26 
pages and had 96 claims. It is doubtful if Fritts did anything prac- 
tical; he confined himself to putting down a large number of ideas 
and variations on paper. Claim 84 of his patent reads "The method 
of making a sound record which consists in photographically affecting 
a sensitive surface in accordance with sound waves". 

1886: A. G. Bell, C. A. Bell, and S. Tainter patented both a 
variable-area and variable-density method of recording a sound- 
modulated light beam through a small slit upon a photographic 
film. 6 Both a physical slit and an optical slit are disclosed. 

This seems to me to be an important patent that has heretofore 
been overlooked. It clearly anticipates Ries, as may be seen from 
the following quotations : "According to the record part of the inven- 
tion a variable beam of light is caused to pass through a fine slit or 
other opening, and an image of the slit enlarged, diminished, or of the 
same size is then projected, by means of one or more lenses or other 
suitable devices upon a sensitized tablet which is moved progressively 
in front of the slit"; and "Sometimes it is desirable to use a second 
slit close to the recording tablet". 

1887: The work of Hedick, a Dutch inventor, using flames that 
could be varied by sound waves, should be noted. 7 

1887: C. J. Hohenstein patented a more sensitive method of 
recording a sound modulated light beam "by reflecting light from a 
small pivoted mirror several times, focusing beam of last reflector, 
which is parabolic, upon a photographic film". 8 This is quite similar 
to the optics of the recording system later developed by General Elec- 

1892: Demeny's "Chronophotophone" combined a disk phonor 
graph and a magic lantern arranged with slides. 9 



Vol 48, No. 4 

1894: Edison brought out the "Kinetoscope." 10 This was a 
peep-show device using ear tubes to catch the sound, and rather 
crudely brought about synchronization of sound and picture. 

1900: J. Poliakoff filed a patent application on the focusing of a 
light beam upon a photoelectric cell, through a positive photo- 
graphic sound record moving uniformly across the beam, the photo- 
electric cell being connected to a telephone circuit. 11 This disclosure 

is interesting in that it men- 
tions the first use of a positive 
record and also a photoelectric 
cell for reproducing. 

1901: Ernst Ruhmer began 
publication of his work on 
sound recording. 12 Since he was 
a professor, his interest was 
more academic than commer- 
cial. He devised the "photo- 
graphophon " , an instrument 
something like the sound 
camera of today. With this he 
recorded and reproduced speech 
using arc lights and Gehrke 
tubes as light sources, and 
selenium cells in reproducing. 
His film speed was rather high, 
being of the order of three 
meters per second. Ruhmer 's 
original "photographophon" 
and some sound records were 
brought to this country by the 

Fox Film Corporation. The apparatus was practical and the records 
show clear definition of the recorded sounds (Fig. 1). Although 
Ruhmer never commercialized his work, he says in one article: 

"For practical uses the application of the photographophon in com- 
bination with the kineomatograph whereby on one and the same film 
both motion and speech may be recorded should be kept in mind." 
Also in another article, "As far as simplicity is concerned the glow 
light tube surpasses all other previous means for the perception of al- 
ternating current curves." 

FIG. 1 . Photograph of Ruhmer 's sound 


1902J An inventor named Hulsmeyer obtained a patent on 
producing photographic sound records. 13 This describes "an oscillat- 
ing mirror which is varied by sound-electric impulses and which re- 
flects a beam through a plate on a photographic strip, through a slit, 
said plate having a transmission varying in the direction of motion of 
the reflected beam in proportion to the sine of the angle". 

1902: On November 8 a patent application was filed by William 
Duddell covering a method of variable area recording and repro- 
ducing, under the title of "An Improved Phonograph". The patent 
shows a comprehensive knowledge of the subject and mentions 
making photographic copies. 

1903 : Wilhelm Asam filed a patent to produce records for phono- 
graphs using a reflecting diaphragm to modulate a light beam. 14 

1904: F. W. LeTall patented a method for modulating elec- 
trically a vapor discharge. 15 

1904: A patent was granted to V. Poulsen (filed in 1901) on a 
method of magnetizing a moving paramagnetic wire or tape by 
means of sound waves. 16 It also showed means of demagnetizing or 
obliterating the magnetic variations along the wire. 

1906: Eugene A. Lauste, formerly an Edison employee, with 
Robert R. Haines and John S. Pletts filed a patent application on 
"method and means for simultaneously recording and reproducing 
movements and sounds". 17 Although Lauste has been credited by 
some writers as having the master patent on talking pictures, one is 
impressed upon examining his patent that he really does not express 
himself too clearly regarding his technique. 

1907: J. F. Dirzuweit patented a photographic method of re- 
cording and reproducing sound. He also shows the use of a gas 
discharge tube for recording. The claims of this patent are rather 
broad, for instance, "Claim 8 A sound recording apparatus com- 
prising a photosensitive surface and a source of actinic rays mov- 
able relative one to the other, and means for exciting said source of 
actinic rays by and in accordance with sound waves". 

1907: Carl Laemmle, of Universal Pictures Corporation, tried 
to commercialize the "Synchroscope", a system using a phonograph. 18 
He achieved some success, but it was found that the regular records 
used were too short. 

1907 : Dr. Lee de Forest filed his patent application on the ' ' Aud- 
ion" covering the addition of a third electrode or grid to the Flem- 
ing valve. 19 This became a basic patent of great importance, as it 

280 E. I. SPONABLE Vol 48, No. 4 

showed the way to make amplification of electrical impulses possible. 

1908: A. Manuelli, a resident of Italy, obtained a French patent 
having "as its object a bicinematographic photophonic machine 
for public and private displays adapted to insure fixedness of pro- 
jection, stereoscopic effect, photographic reproduction of sound, 
etc. " He describes a complicated machine using three films . 20 

1908: About this time Edison again brought out another ver- 
sion of his talking picture device, this time called the "Camera- 
phone". The picture was photographed to synchronize with a 
phonograph record. As no close-ups were then employed, exact 
synchronism was not an important factor. It was accepted for a 
short time only, as a novelty. 

1908: J. F. Child patented the making of a photographic record 
of a manometric gas flame and the use of selenium in reproducing 
the record. 21 

1910: R. O. P. Berglund, of Sweden, patented recording sound 
using a mirror attached to a microphone diaphragm, thus modulating 
a light beam and recording the variations on a sensitive disk or 
film. 22 

1911: C. G. Timm obtained a Swedish patent similar to that of 
Berglund. 23 

1911: F. D. Pudumjee, of India, described a method of using a 
mirror attached to a vibrating diaphragm to produce a photophono- 
graph. 24 

1912: I. H. MacCarty, a resident of the United States, obtained 
a French patent covering "simultaneous recording by means of 
photography upon one and the same films of animated views and 
articulate or other sounds with a view to insure synchronous repro- 
duction of such views and sounds". 25 (His drawing of a combined 
sound and picture film showed a much keener appreciation of the 
problem than was shown by Lauste.) 

1913: Edison brought out the "Kinetophone". 26 This appara- 
tus tried to create synchronism of picture and sound by using a belt 
connection between a phonograph on the stage and a projector in 
the picture booth. It had a run of about sixteen weeks in the 
B. F. Keith theater in New York, but attained no great commercial 

1913: A patent application for recording sound filed by E. E. 
Ries was granted in 1923. 27 The following claim from the recording 
patent gives an idea of its scope: Claim 14 "The method of 


producing motion pictures and photographic sound records concur- 
rently upon the same photographic film, which consists in moving a 
photographic film through a camera at a speed adapted to produce a 
given number of pictures per second, simultaneously moving said film 
at the same rate per second across the back of a screen having a nar- 
row aperture which exposes the sensitized surface to light in a con- 
tinuous line or band parallel to the line of pictures and of uniform 
width throughout its length, limiting the area of exposure to the area 
of the aperture, and varying the degree of exposure of said line or 
band in accordance with sound waves impressed upon a sound trans- 
lating device, whereby said sensitive surface when developed will pre- 
sent adjacent to the pictures a continuous line or band of uniform 
width and having alternating sections of varying degrees of density 
of translucency representing continuous waves corresponding to the 
sound waves impressed upon the sound translating device." 

A similar patent covering reproducing was also filed in 1913 and 
granted in 1926. 28 

In view of the decision in the de Forest-Stanley case, where the Ries 
reproducing patent was held infringed, it is interesting to note that 
Ries came to Auburn to see Case in 1923 and offered to sell his pat- 
ents for one thousand dollars. Also, that opinions by Thompson and 
Gifford (Mr. Case's patent attorneys) in 1925 were to the effect that 
it was very doubtful that these patents would be upheld in Court. 
Ries later sold these patents and several other applications to the 
de Forest company. 

1914: H. G. Stocks filed a patent application covering the proc- 
ess of recording sound photographically by modulating a mercury 
lamp for the purpose of making an optical phonograph. 29 

1915: H. C. Bullis filed a patent application that was granted 
in 1920, describing a double system method of recording sound and 
picture on separate films, running synchronously through a single 
machine, and the use of marking lights to enable matching of 
sound and picture after the films were processed. 30 

1916: T. H. Nakken obtained a patent on a means for con- 
verting sound waves into light variations; also a patent on means 
for transforming light impulses into electric current impulses. 31 

The various Nakken patents were purchased by the Warners, after 
having been offered for sale for some time by the inventor. 

1918: A. C. Rutzen received a patent to engrave a sound track 
on a moving picture film adjacent to the picture. J. Ballance 

282 E. I. SPONABLE Vol 48,- No. 4 

received a similar patent in 1906. Again in 1926, E. H. Foley pro- 
posed the use of a separate film for an engraved sound record. 
None of these methods has been practical. F. L. Madelar cut his 
record on the back of the film in the nitrocellulose base with a dia- 
mond stylus. Later, similar patents were granted to A. L. Curtis 
and J. Kaiser. 32 

1918 on: During the summer of this year, experimental work 
was begun by the German Tri-Ergon group consisting of Josef Engl, 
Joseph Massole, and Hans Vogt. 33 They worked out a system of 
making sound motion pictures using a glow discharge lamp in photo- 
graphing the sound. The sound was recorded on special film having 
standard-sized pictures and a space outside of the sprocket holes for 
the sound band. At the time this system was brought to this country 
by Fox (1926) it had many novel features but the results were quite 
inferior to those obtained by Fox-Case methods. 

Tri-Ergon obtained about eighteen patents on their system between 
April 1919 and July 1923. Some of these patents such as the print- 
ing patent, the flywheel patent, and the photoelectric cell patent 
were so basic that they later were the cause of extensive litigation and 
nearly became controlling factors in sound recording and reproduc- 
tion. The Supreme Court reviewed the flywheel patent and held it 
invalid (Mar. 4, 1935). 

1918 on: J. Tykociner, at the University of Illinois, worked out a 
system for producing talking pictures. 34 This work was quite aca- 
demic and no attempt was made to commercialize it. Variable-den- 
sity recording was used. Sound and picture were combined on the 
same film, the sound track being placed inside the sprocket holes and 
adjacent to the pictures. The system was called "Phonactinion". 
The sound was recorded by modulating luminous gas discharge de- 
vices. Tykociner 's paper contains a rather extensive discussion on 
recording sound. He made several demonstrations before scien- 
tific societies. Later he suggested a novel means of recording 
that was considered quite seriously by Case at one time. This con- 
sisted of forming a glow discharge between two closely spaced semi- 
conductors in air. The separation of the electrodes acted somewhat 
like a slit, in that it limited the area of exposure on a photographic 
film placed adjacent to the glow. So far as I know, the merit of this 
method of recording has never been verified. 

1920: D. A. Whitson filed a patent application for producing 
sound records by passing a beam of light through a Kerr cell, 


and modulating the latter magnetically, the resulting light being 
photographed on a moving film through a slit. 35 

1921: Prof. H. O. Rankine, of England, worked out a method 
of recording sound photographically using a constant light source 
and controlling the light beam from this source by means of a me- 
chanical "light valve". He used one fixed grid and one movable 
unit that was controlled by the sound impinging upon a micro- 
phone diaphragm. This work was academic and in the nature of a 
laboratory demonstration. 

1921: Grindell Matthews devised a mechanical method of re- 
cording sound photographically by producing vibrations of a beam 
of light from a constant light source. 

1921: A demonstration by Professors Aurbenius and Montellius 
was described in the London Times, Sept. 24, 1921. Two films were 
used, one for picture and one for sound. They were run in separate 
machines geared together. The sound record was produced in a 
manner similar to that employed by Matthews. 

1923: The Peterson- Poulsen system was worked out in Den- 
mark. 36 It used a variable-area method of sound recording on a sepa- 
rate film run synchronously with camera and projector. The sound 
record was made using an oscillograph and a small slit. The process 
was exploited by Tonfilm, in Germany. The reproducer used a sele- 
nium cell. 

1923: A United States patent was issued to E. Peterson, show- 
ing a variety of arrangements of a magnetic wire imbedded in the 
marginal portion of a motion picture film. 


The results secured by the early workers were, by limitation of ex- 
isting equipment, rather crude and did little more than demonstrate 
the principles of sound recording and reproduction. It was Theodore 
W. Case who, more than anyone else at this time, began to realize 
that, if sound pictures were to serve as a medium for entertainment, 
it would be necessary to perfect the system to such an extent that the 
illusion created in the reproduced sound and pictures be good 
enough to make one forget the mechanics of the system and think 
only of the event portrayed. Accordingly, in putting together the 
Case system each step was studied and developed with the idea of 
incorporating the best engineering practice available at the time. 
The way was made easier because of the developments made during 

284 E. I. SPONABLE Vol 48, No. 4 

the first World War, including improved microphones, better vacuum 
tubes, amplifiers, loudspeakers, etc. 

1911: Case began experimenting on sound recording while a 
student at Yale. In a letter to his mother, Jan. 22, 1911, he writes: 
"Most of my time now is taken up in experimenting with my Sele- 
nium Cell with the idea in mind of photographing sound waves and 
using the positives as records for a new kind of Phonograph or 
rather it would be called a Lithograph I suppose." 

And on Feb. 12, 1911 he writes: "Yesterday I at last succeeded 
in transmitting sound by light. I used the principle of the mano- 
metric flame. The eye could not detect the variation of the light 
at all but it was registered perfectly in the varying of the resistance 

FIG. 2. The original laboratory built by Case in 1916 for his research work. 

of the selenium. The reproduction of the voice was perfect. Next, 
I have to set up an apparatus for my delicate photographing of the 
light variations. It is very interesting work and gives me some- 
thing to do alright." 

1913: Case began experiments at Auburn, New York, and de- 
voted himself to trying to find a practical means of converting light 
into electricity. 

1916: E. I. Sponable, upon graduating from Cornell, joined 
Case and with him started the Case Research Laboratory. Case's 
experimental work was moved from the cellar of his home at 196 
West Genessee Street to a new laboratory designed by Sponable and 
built at 205 West Genessee Street (Fig. 2). A three-stage audion 
amplifier was purchased from the de Forest company. This was 
used to test a large number of crystals and minerals for the prop- 
erty of changing resistance when illuminated. Aboi't nineteen new 


substances were found and studied. It was at this time that Case 
first met de Forest. 

1917: The "Thalofide" Cell (containing a light sensitive change- 
of -resistance material similar to selenium but a form of thallium 
oxy-sulfide particularly sensitive to infrared radiation) was dis- 
covered (Fig. 3). 37 This was used as the receiving element in an in- 
frared signal and communication system developed for and used by 
the Navy during the first World War. During this time the Case 

FIG. 3. Thalofide Cell, high vacuum, helium, 
or hydrogen filled. Case Research Laboratory, 
Inc., Auburn, N. Y. 

Research Laboratory, working in conjunction with the Naval Experi- 
mental Station at New London, Connecticut, was entirely devoted to 
war work and carried on extensive research in the transmission and 
amplification of speech and signals in connection with its infrared sys- 

1918 to 1922: De Forest began work on talking motion pictures. 
He filed patent applications on methods of recording in 1919, and 
during 1922 carried on experiments in Germany trying to record 
sound by modulating a high-frequency gas discharge tube. 38 

286 E. I. SPONABLE Vol 48, No. 4 

1920 to 1922: Case discovered the barium photoelectric cell and 
began its development. 39 In its final form it was used in a recorder for 
making permanent records of the light variations of daylight and 

1920: De Forest purchased Thalofide Cells from the Case Re- 
search Laboratory. 

Oct. 1922: Case saw de Forest in New York regarding extrane- 
ous noises in Thalofide Cells that de Forest was trying to use for re- 
producing sound. 

Oct. 1922: Case, while in London, witnessed a demonstration 
of Rankine's experiments in sound recording. 

Nov. 1922: Upon his return from abroad, Case was invited by 
de Forest to visit his studio. De Forest spoke of trouble he was hav- 
ing in trying to record sound with high-frequency discharge tubes. 
He exhibited and reproduced a short piece of sound film. This was 
barely understandable. He apparently was about at the stage he 
speaks of in his SMPE article 40 "I well remember the grim satisfac- 
tion I felt when, for the first time in reproducing a photographic rec- 
ord of my voice, I was able clearly to determine whether or not it was 
being run backwards!" 

Nov. 1922: A crude sound camera was made at the Case Labo- 
ratory and a sound picture made of a modulated oxy-acetylene 
flame. This was the same manometric flame that had previously 
been developed for use in infrared telephony. 

De Forest at this time tried recording with tungsten filament 
lamps with practically no success. Case suggested to him the use 
of a hydrogen-filled lamp as having faster reaction. The Case 
Laboratory made up several hydrogen-filled flashlight lamps for 
de Forest, and also tried some of them for sound recording using a 
four-stage amplifier. The results were poor because of the large 
amount of unmodulated light. 

Dec. 1922: De Forest's relations with Case are indicated in the 
following excerpt from a letter from de Forest to Case : 

"As per our telephone conversation I am mailing you today six 
blanks, two of each capillary diameter. Kindly fill these with nitro- 
gen and exhaust as soft as possible, i. e. to give them maximum bril- 
liancy and minimum voltage. Paint with bronze the two balls at each 
end of the tube and wrap same carefully with tinfoil and glass. Then 
apply to these terminals alternating high voltage. 

"I hope you can get these tubes to light up at 3000 or 4000 volts. 


You might put in a needle spark gap in shunt as approximate voltage 

"I suggest that you put a drop of mercury in some of these tubes to 
see if this does not considerably soften the discharge, at least when the 
tubes get hot enough to liberate the mercury. I am also requiring you 
to be so good as to make up two or three ballast resistances using very 

FIG. 4. Present-type Aeo light (July 1928). 
Case Research Laboratory, Inc., Auburn, N. Y. 

fine tungsten filament and hydrogen gas. Believe that the bulb lamps 
are usually filled with hydrogen at atmospheric pressure, but am not 
informed on this point. 

"I believe if I can get a proper ballast system in series with the 
short filament lamp I can record the voice photographically by this 
means. This, of course, is an ideally simple matter compared with the 
high-frequency light. 

"I shall await receipt of these tubes and your further suggestions 
with great interest." 

288 E. I. SPONABLE Vol 48, No. 4 

1922: Case iFound that the gas discharge in an argon-filled 
vacuum tube whose filament was coated with alkaline earth oxides 
could be easily modulated at a low voltage, and it seemed to Case 
suitable for sound recording purposes. This tube had been previously 
used in his infrared signal system. This observation led to the de- 
velopment of the Aeo light, and was a big step in making this system 
of sound recording practical. Previous to this discovery by Case, 
de Forest had been using nitrogen-filled tubes operating on a high- 
frequency circuit at 3000 to 4000 v and giving a very limited photo- 
graphic light output. The Aeo light operated on direct current at 200 
to 400 v, and gave off radiation which was highly actinic. (Fig. 4 
shows Aeo light as finally developed in 1928.) 

1922: A Powers projector was converted into a sound camera at 
the Case Laboratory. Also the Aeo light was improved by using 
helium gas instead of argon, thus increasing its actinic light. Soon 
it was found that these recording lights could be operated without 
heating their cathodes. 

The following abstracts from the Case Research Laboratory 
records indicate the stages in the development of sound recording 
during the period from 1923 to 1925, inclusive: 

Jan. 10, 1923: A conference was held among Case, Sponable, 
and Thompson (patent attorney for Case) to discuss the patent- 
ability of Helio light (later named Aeo light) . 41 

Jan. 11, 1923: It was found that nonoxide coated filaments in 
vacuum tubes were not good for sound recording and that a cathode 
discharge was more desirable. 

Jan. 13, 1923: Case wrote to de Forest telling him that oxides 
in the recording lights effected an improvement when the filaments 
were operated cold. Later it was found that this oxide coating was 
photo -active. 

Jan. 26, 1923: A letter was received by Case from de Forest 
about the lights containing oxides. It also mentioned trying two 
small ball electrodes, oxide coated. This proved impractical be- 
cause the area was not great enough on small ball electrodes and an 
arc discharge started too easily. 

Feb. 10, 1923: Case suggested to de Forest that he remove the 
lens from the Helio light system to get rid of "blasting" he had been 

Feb. 14, 1923: A new sound camera designed by Sponable and 
built by the Precision Machine Company of New York was 


completed and first tested. Sound records were made with good 

Feb. 23, 1923: Case and Sponable visited the de Forest studio 
in New York. De Forest's first combination of pictures with sound 
was seen and heard. These were made using Case Helio lights. 
The forming of a company was discussed and a contract permitting 
de Forest to make commercial use of Aeo lights and Thalofide Cells 
was negotiated but not signed. 

Mar. 5, 1923: De Forest notified Case he had completed eight 
combination pictures. 

Mar. 13, 1923: De Forest exhibited his sound motion pictures to 
newspaper men at his New York studio. At this exhibition, the 
sound system included a Case helium-nitrogen filled barium-oxide- 
coated recording lamp operating on direct current at low voltage 
and giving a moderately concentrated glow on the plate cathode. 
A Western Electric amplifier provided the driving power for the 
Helio light. The Case Thalofide Cell was used in the reproducing 
system. De Forest, in his discussions with the press, referred to the 
Case Helio light as his "Photion". The reproduced sound showed 
bad mechanical motion and poor quality. 

Mar. 14, 1923: Case suggested, in connection with his recording 
lights, the use of an oxide-coated filament as a cathode. This re- 
sulted in more light and longer life. 

Mar. 17, 1923: DeForest wrote to Case saying that the latter's 
efforts "to improve his photion light were well justified so Phonofilm 
could be brought out soon" and that Case was entitled to broad 
claims on the oxide-coated filament. De Forest said he would give 
Case full credit for work done in perfecting his Photion tube. 

Apr. 4, 1923: De Forest gave a demonstration of his sound 
pictures before the New York Electrical Society. In describing 
his recording light he stated he was using a high-frequency gas 
light; he gave Case credit only on the Thalofide Cell, and for 
valuable suggestions and improvements to "Phonofilm." 

Apr. 15, 1923: The first public exhibition of de Forest "Phono- 
film" was given at the Rivoli Theater, New York. 

Apr. 18, 1923: Case perfected the Therrnophone for use as a 
microphone. This was used in making many of his early sound 

May 7, 1923: It was found that helium purified in a calcium 
arc further lowered the operating voltage of Helio lights. 

290 E. I. SPONABLE Vol 48, No. 4 

May 13-14, 1923: Case and Sponable visited the de Forest studio 
and observed weaknesses in de Forest's methods of sound recording 
and reproduction. 

June 28, 1923: The Precision Machine Company rebuilt the 
Case sound camera in an effort to reduce the amount of flutter it was 
causing in the recording of sound tracks. 

July 3, 1923: A letter received from de Forest said that the 
Case Helium Photion light "had gone bad". It had been in use 
since May 7, 1923, and the letter raised the question as to whether 
it should be recoated. De Forest suggested that adding a trace of 
mercury would avoid certain British patents. 

July 11, 1923: De Forest cited a German patent which contained 
an admission that it is old in the art to use a discharge containing a 
metallic vapor. De Forest used this patent on which to base his 
belief that any existing patent difficulty could be avoided by in- 
troducing mercury. It was possible that the coated electrode of the 
Aeo light producing green barium vapor in the discharge would be 
equivalent to introducing a metallic vapor. 

Aug. 30, 1923 : The contract referred to under date of February 
23, between the de Forest Phonofilm Company and the Case Re- 
search Laboratory, was consummated. This contract granted de- 
Forest a commercial license to use Aeo lights and Thalofide Cells in 
taking and reproducing sound pictures. 

Aug. 31, 1923: The following quotation is taken from the Case 
Laboratory notes: "A trip was made to New York for the pur- 
pose of aiding the de Forest Phonofilm Company in setting up their 
9- A amplifier and also to test out the Case air-thermo microphone un- 
der studio conditions. A comparison of the static microphone using 
the old set-up previously made at the studio with the same micro- 
phone using the 9- A amplifier was made. These two films were also 
compared with a film made using the air-thermo microphone on the 
9- A amplifier system. At New York, it appeared that the voice re- 
production on the air-thermo microphone was slightly better and 
clearer than the records made using the static microphone. The films 
when run at this laboratory, seemed to indicate that there was little 
difference in these films; if anything, the static microphone was of 
slightly better quality. 

"De Forest was shown our method of wiring up the 8- A and 9- A 
amplifiers for reproducing. This system was a great improvement 


over the two 7-A boxes which he was using. This improvement was 
in quality rather than loudness. 

"A number of experiments of the talking moving pictures were wit- 
nessed at the Phonofilm studio. These indicated that the product 
had been greatly improved over the old films seen on previous trips. 
In the case of music records the film from this laboratory seemed to be 
of slightly better quality than those shown there." Both Case and 
Sponable were present during these conferences. 

Oct. 8, 1923 : De Forest informed the Case Laboratories that he 
now had twenty-five films worthy of exhibition in theaters. Did we 
have a supply of Aeo lights? 

Nov. 14, 1923 : De Forest mentioned a recording he had made of a 
speech by Dr. F. Crane, saying "one can understand every word first 
time through." 

Dec. 7, 1923: De Forest said that the thermo-microphone sup- 
plied him by Case was "wonderful", and that the Aeo light was 
"working fine". 

Jan. 23, 1924: For recording sound, de Forest had originally used 
an optical system imaging the glow discharge on a slit of the order 
of three mils wide; it now occurred to him that a narrower slit, 
say 1.5 mils, might be better. He recognized the problem of get- 
ting sufficient light with the narrower slit. 

Jan. 1924: Sponable had considered the redesign problems in- 
volved in converting a Bell and Ho well camera for recording sound 
on the same film with the picture. Bell and Ho well was authorized 
to rebuild one of their cameras in accord with this design, which in- 
volved photographing the sound at the sprocket through a slit in 
contact with the film and with the Aeo light placed directly behind 
the slit. 

Feb. 8, 1924: In the same way, a Bell and Howell standard pic- 
ture printer was redesigned to provide both sound and picture 
printing apertures and exposure control shutters. This work was 
done locally. 

Feb. 8, 1924: Case wrote: "I think it would be better to do 
away with the slit entirely in the sound reproducing chamber as a 
slit is liable to become dust clogged being so small and the best 
method of procedure will be to construct a light with a very fine 
short straight filament and place a lens in front of this so as to suit- 
ably produce an image of the filament which may be brought to the 
size desired, say one and one-half thousandths of an inch and allow 

292 E. I. SPONABLE Vol 48, No. 4 

this image to pass through the sound record, spread, and then cover 
the Thalofide cell." 

Spring 1924: De Forest had about twenty outfits giving road- 
shows in theaters. 

Feb. 28, 1924: A letter received from de Forest explained lack of 
Case publicity and stated that Phonofilm was a combined invention 
of de Forest and Case. 

Mar. 25, 1924: The Bell and Howell camera modified for sound 
was received at Auburn and was tested. The motion was unsatis- 

(Courtesy RADIO NEWS magazine) 

FIG. 5. First Case sound newsreel outfit. Published in RADIO NEWS, 

November 1924. 

May 9, 1924: Case suggested that the slit be protected by plac- 
ing a glass wedge in the slit opening. Previous slits were susceptible 
to dirt and dust and were cleaned by opening and closing, or by an 
air jet. 

July 9, 1924: E. B. Craft, of the Western Electric Company, 
advised Case and Sponable that Western Electric would probably be 
willing to grant a license for the Laboratory to use amplifiers com- 

July 25, 1924: De Forest began using the Case design of camera 
in which the sound was photographed on the film at the sprocket 


position. (This same method of recording is still in use in newsreel 
cameras today.) 

July 25, 1924: De Forest asked Case to make recordings of 
Coolidge and La Follette in Washington. De Forest was to supply a 
professional cameraman. (These pictures, photographed on Aug- 
ust 11, were the first news sound pictures of importance ever 
made Fig. 5.) 

Aug. 1924: A small sound recording studio was constructed in 
the basement of the Case Laboratory. This consisted of a room 
about 10 ft sq with a 6-ft ceiling. The walls were made of hair felt. 
The camera was placed outside of the studio and its lens imaged the 
interior through a hole in one of the studio walls. 

Incandescent lighting was used to the extent of twelve 1000-w 
lamps. The subject could not exist in the studio for more than a few 
minutes at a time without coming out for air. 

Dec. 8, 1924: To indicate the general character of work at the 
de Forest studio the following is taken from notes of Dec. 8, 1924: 

"A visit was made to the de Forest studio. Reproduction was heard 
on the de Forest system using the slit arrangement. It was found 
that their slit was set at about four mils. When this was brought 
down to one and one-half mils the reproduction was very good, al- 
though the quality was not quite as good as with the focused filament 
arrangement. A focused filament set-up was made for de Forest using 
some lamps made in his factory. In these lamps the filament was held 
straight by spring tension, being the same arrangement as used in his 
amplifier tubes. The filament diameter of the lamps used was about 
one-half mil. The reproduction on this focused filament arrangement 
seemed to be very good. The Vitalux lens was used and improvement 
will probably be noticed when de Forest obtains the special Bausch & 
Lomb 1 : 1 objective which we had developed. 

"Aside from a noticeable improvement in his reproducing apparatus 
the situation at the de Forest studio had not changed appreciably. He 
had made a number of Phonofilms. One, a Christmas number, in- 
cluded a song by Mme. Rappold in a Christmas tree setting followed 
by a church scene with choir boys singing and ending with a trumpet 
chorus in supposedly a heavenly setting. All of this number was 
slightly sour and it is doubtful whether or not it could be used commer- 

Jan. 12, 1925: Case devised a slit with cover-glass protec- 
tion. 42 This was a very important step in making sound recording 



Vol 48, No. 4 

practical. This slit consisted of a small piece of quartz about 0.25-in. 
square and 0.04-in. thick. One side was coated with chemically de- 
posited silver and a slit about 0.001 in. X 0.120 in. was ruled in this 
silver coating. A thin cover glass was then cemented on top of the 
silver and the cover glass was ground and polished down to a thick- 
ness of less than 0.001 in., including the cement (Fig. 6). The slit was 
then mounted in a steel shoe that could be placed in contact with the 
film at the camera sprocket. The Aeo light was set close to the quartz 
slit, thus eliminating the use of a lens to focus the glow discharge on 

FIG. 6. Quartz camera slit. Case Research Laboratory, Inc., Auburn, N. Y. 

the film and ensuring the maximum amount of light reaching the 
film (Fig. 7). 

May 13, 1925: De Forest borrowed the rebuilt Bell and Howell 
camera from Case in order to make sound pictures of Dr. Elliott in 

Sept. 1925: Business complications terminated the working ar- 
rangement between de Forest and Case. Case, having gone this far 
in the talking picture field, decided to continue the work and finish 
up some of the technical problems that were still not solved. 

During the fall of 1925, the Case Laboratory started building their 
first sound reproducing attachment. After considerable deliberation 
it was decided to design this to operate below the projection head 


rather than above, as had been de Forest's previous practice. This 
was decided upon for three reasons : First, it was desired to incorpo- 
rate a large flywheel that would give sufficient inertia to iron out all 
inequalities that might be transmitted from the projection head. 
Second, in the Bell and Howell camera the sound came after the pic- 
ture and a better printer design was possible if the sound was not 
transposed to a position, ahead of the picture. And, last, which 
seemed important at that time, an attachment was wanted that 
would not run sound films previously made, which in some instances 

FIG. 7. Remodeled Bell and Howell camera for sound recording. Case Re- 
search Laboratory, Inc., Auburn, N. Y. 

were quite bad. Sponable laid out this design and supervised local 
mechanics in executing it. It was here that the industry received its 
14i/ 2 -i n . hangover the sound and corresponding picture were dis- 
placed by 14V2 in. or 20 frames. This early attachment was very 
similar in principle and design to the present ERPI type 206. 

Sept. 14, 1925: It became apparent that great mechanical accu- 
racy was required in making the recording camera; this is empha- 
sized by the following quotations from the Case Laboratory records : 
"The camera was received back from Bell & Howell Company on 
September 12. Tests were begun on this camera September 14. 
The first test taken was made of voice and piano. When this was 

296 E. I. SPONABLE Vol 48, No. 4 

reproduced it was found that the camera still had a bad sprocket pulse. 
The eccentricity of the sprocket was determined with an indicator. 
It was found that it was running off about .5 of a mil on one end and 
.7 of a mil on the other. This, together with a noticeable high spot 
in the gears, was sufficient to account for the pulse observed." 

"We tried the shaft alone in its bearing and found that it was run- 
ning fairly true. The sprocket, when tried alone on an arbor running 
true, was found to be 2 J /2 mils off and also slightly out of round. We 
made inquiry as to the best machinists around here and after trying 
a number of shops found that Doyle & Wall, 322 Pearl Street, Syra- 
cuse, seemed to be the best to do further work on the camera. They 
are used to working with a tolerance of .1 mil and seemed to fully 
appreciate our problem." 

Nov. 23, 1925: "After returning to Auburn Case went over the 
patents on sound recording and after calling Mr. Thompson into 
conference it was decided that the field was much more open than 
we had previously supposed. De Forest gas discharge patent seemed 
to be limited to the use of alternating current. Also it seemed ques- 
tionable whether a court would uphold such patents as the Ries and 
the Fritts. Mr. Thompson was sent to New York to get the opinion 
of Mr. Gifford, supposedly one of the best attorneys in the matter of 
patents. Mr. Gifford 's opinion in this matter seemed to confirm 
Thompson's, that is, that the field was open and that no .one seemed 
to have any fundamental patents on the system of talking moving 

Dec. 8-10, 1925: "About a year ago we approached the Western 
Electric Company regarding the use of their amplifiers or commer- 
cial showing of the talking pictures. At that time Mr. Craft 
advised us to go ahead and use them for this purpose and stated 
within a few weeks the Western Electric Company would submit a 
contract to us covering some form of a license agreement. Nothing 
further happened regarding this agreement at that time. Now that 
we are interested in using these amplifiers for possibly road show 
work and having severed connections with the de Forest outfit E. 
I. Sponable went to New York for the purpose of seeing Mr. Craft and 
if possible, obtain his O.K. to go ahead with their amplifiers for any 
commercial work we should want to do." 

"On seeing Mr. Craft we explained to him the situation and re- 
called to his mind our conversation of last year. He stated that since 
that time considerable water had gone over the dam and that they were 


now interested in talking moving pictures themselves. Further, that 
they were negotiating or had completed negotiations with Warner 
Bros, to furnish the latter company with apparatus and technical 
aid to enable this moving picture firm to produce and market talking 
moving pictures. Considerable discussion of the subject resulted in 
Mr. Craft's saying that he believed we were further along in the art 
than they were and that he saw no reason why both the Case Research 
Laboratory and the Western Electric Company should not get to- 
gether and compare their accomplishments and possibly enter into 
some agreement with a moving picture company whereby both the 
Western Electric Company and the Case Research Laboratory would 
benefit. He further stated that he would like to send two of his 
technical men up to Auburn to hear our films and look over our de- 
velopments. After they had returned and reported to him he would 
then try to arrange a meeting between representatives of this labo- 
ratory and the commercial men of the Western Electric Company." 

"Before the call on Mr. Craft the Keith-Albee people were visited 
for the purpose of determining whether or not they would be inter- 
ested in obtaining our talking moving pictures for an act of .vaude- 
ville. Mr. Oakford of the booking department of the Keith people 
was given information regarding our system. He was very much in- 
terested in what we told him and stated that he would take it up with 
men higher up in the company and advise us regarding their interests. 
He reported the following day that he had talked with the vice presi- 
dent of the Keith company and that the latter was very much dis- 
turbed to think that he would dare to bring up the subject of talking 
moving pictures to them again. They admitted that they had been 
stung on the thing twice, once about fifteen years ago where they 
invested considerable money in stock of a talking picture outfit, and 
later in certain connections with the de Forest company. The vice 
president of the Keith company stated positively that they were not 
interested in talking moving pictures." 

Dec. 15, 1925: "In our conference with Mr. Craft last week, he 
intimated that the use of amplifiers in talking moving pictures 
would come under their public address work and that at least for 
two or three years we would be unable to use amplifiers for this 
purpose without the permission of the Western Electric Company." 

"In order to check up this point it was thought best to talk it over 
with Dr. W. R. Whitney of the General Electric Company. This was 
done by E. I. Sponable on December 15. Dr. Whitney stated that 

298 E. I. SPONABLE Vol 48, No. 4 

the situation was really something that Mr. A. G. Davis (vice presi- 
dent of the General Electric Company) was more fitted to give an 
opinion on than he. After describing the situation to Mr. Davis he 
stated that he believed that the talking moving pictures did not come 
under the public address work and that at present the amplifier situa- 
tion was quite muddled, there being almost an endless number of 
patents in this connection. Sometime within the next year they hope 
to clear this situation by placing all these patents in the hands of the 
Radio Corporation. Mr. Davis stated that he believed we should see 
Mr. David Sarnoff, president of the Radio Corporation, and get his 
opinion regarding our requirements. He very kindly suggested that 
he would arrange such a meeting for us and is doing so at the present 

"Dr. Whitney as usual was very nice in this connection and took the 
attitude that he was particularly anxious to aid anyone who was 
doing good research like the work carried on at the Case Research 

Dec. 17, 1925: "Dr. Crandall and Dr. MacKenzie of the Bell 
Telephone Laboratories were sent here by Mr. Craft. They were 
shown our talking films and all parts of the taking and reproducing 
system were explained to them in detail." 

"We gathered from them that our films were very good. They 
stated that they believed that in their own recording that their 
ground noise might be slightly less but discounting the fact that we 
were not using as good loud speakers or telephone equipment as 
they have they thought our stuff to be remarkably good. They noted 
the simplicity of design of the camera and projector and commented 
on the fact that such a design could be readily commercialized." 

"We gave them data concerning our photoelectric cells and record- 
ing lights. They stated that they would like to order these various 
devices so that they could determine their constants using their own 
apparatus at the Bell Laboratories." 

Jan. 4, 1926: An opinion was received from Mr. Adams, head of 
the patent department of RCA : 

"He stated that due to de Forest's original patent having expired 
that de Forest now had no more right to use amplifiers or to make 
vacuum tubes than anyone else and that the field now seemed to be 
completely controlled by the Radio Corporation as the result of 
patents held by the General Electric Company and relating to the 
manufacture of vacuum tubes and their use in various circuits." 


"With reference to whom has the right to supply amplifiers for use 
with talking moving pictures he stated that this right rested with the 
Radio Corporation or at least would rest with them when certain 
patents now under negotiation are finally turned over to them. Fur- 
ther, that he believed from the agreement with the Bell Telephone 
Company that the Radio Corporation reserved the right to use ampli- 
fiers in the connection with talking moving pictures for themselves." 

Jan. 7, 1926: A meeting was arranged with Adams and his as- 
sociate, Capt. Ranger. 

"The only new thing which developed was at this meeting Adams 
reversed a statement which he had made at a previous conference 
with E. I. Sponable, that is, that both the Radio Corporation and 
Western Electric Company would have rights to use amplifiers for 
talking moving picture work. He stated that he would talk the mat- 
ter over with Mr. Sarnoff and advise us shortly regarding some ar- 
rangement for starting a company to handle the talking picture situa- 

"Previous to this -meeting of Adams and Ranger, Mr. Case and 
Mr. Sponable were at the Bell Telephone Laboratories to see Mr. 
Craft. We told Mr. Craft that we had checked up the amplifier 
situation with reference to talking moving pictures and had found that 
the General Electric Company seemed to - believe that they controlled 
the rights for the use of amplifiers in this connection. Craft then 
stated that it was really something that both companies had a joint 
right in and that in case the General Electric Company should use 
amplifiers for this purpose they would possibly have to obtain per- 
mission to do so from the Western Electric Company. Mr. Craft fur- 
ther stated that he was anxious to get a report from his men regarding 
our Aeo lights and photoelectric cells which they wished to examine." 

"We went down to Dr. Crandall's office where we saw the Western 
Electric system of film recording. Inasmuch as our visit was rather 
unexpected they seemed to have considerable difficulty in getting 
their apparatus to work properly. The showing which they made 
during this exhibition was not impressive to us. They were, however, 
using fairly high quality amplifiers and a laboratory model of a loud- 
speaker which gave excellent and true quality of reproduction. They 
showed a number of records taken of the Capitol Theater music in- 
cluding pipe organ, orchestra and singing. They also showed one 
talking record made in their own laboratories. The talking record 
was not good and when reproduced on a cone such as we use, it was 

300 E. I. SPONABLE Vol 48, No. 4 

extremely bad. Their recording of music reproduced seemingly well 
although possibly part of this was due to the high quality of the music 
recorded, that is, the Capitol Theater orchestra. After hearing these 
records we attended a luncheon with Messrs. Adams and Ranger 
noted above and then returned again to the Bell Telephone Laborato- 
ries. During this time the apparatus had apparently been given an 
overhauling and the showing or reproduction was much better than 
that heard during the morning. It is interesting to note here that 
with the Western Electric reproducing amplifier which they were us- 
ing they found it necessary to add an equalizer to correct for a dis- 
crepancy in their photoelectric cell. Without the equalizer the low 
frequencies came through in great predominance. Adding the equal- 
izer decreased the volume to about Vso and brought the quality to 
approximately normal. Their photoelectric cell was connected to 
the first tube using 20 megohm resistances. In our work we use 
about two megohms across .the cell and about 50,000 ohms across the 
first bulb. It is possible that we compensate for the equalization in 
this manner." 

Jan. 29, 1926: Case and Sponable visited the Warner .Theater to 
see a demonstration of Maxfield's Vitaphone. 

"We all agreed that the showing was very good and of commercial 
quality. However, we believe that our own reproduction was better 
with regard to illusion and naturalness. In the Western Electric sys- 
tem they were using the large public address system thus accounting 
for the large range without distortion. Their loudspeaker was ap- 
parently of the horn type placed above the screen." 

"After lunching with MacKenzie we returned to the Be.ll Telephone 
Laboratories where we met Dr. Crandall and proceeded to Mr. 
Craft's office. Mr. Craft advised us that his men had only made a 
preliminary report to him but it seemed that we had nothing in our 
system which would be of particular use or addition to the Western 
Electric system." 

"Mr. Craft, however, was reluctant to give up our system entirely 
and said he would like to know more about it. Inasmuch as the re- 
production of the film was the real test, we suggested that the West- 
ern Electric Company send us some of their film, both voice and 
music. We could then reproduce it at Auburn and at least satisfy 
ourselves regarding the merits of the two systems. They did not care 
to submit some of their film already taken and stated that they would 
take two numbers and send them up to us the following week." 


"We then left the Western Electric Company and proceeded to 
Captain Ranger's office in the Radio Corporation building. We ad- 
vised Captain Ranger that we were now ready to go ahead with the 
talking pictures with them or arrange for licensing the use of their 
amplifier system. We asked him to bring these things to Mr. Adams' 
attention and arrange for a get-together to talk the situation over. 
After leaving Captain Ranger we stopped at the office of Mr. Gifford 
where we talked over the patent situation. He had already prepared 
an opinion regarding the de Forest and Ries patents, this opinion be- 
ing that these patents were of questionable value. Our talk with him 
seemed to further his conviction regarding their questionable value and 
he stated that he would send us the written opinion in the near fu- 

Feb. 13, 1926: Case devised a way to avoid film splice clicks by 
using graded opaque at the join. 

Feb. 15 to Mar. 1, 1926: Case and Sponable discussed with 
Whitney and Stone (a vice president of General Electric Company) 
the possibility of combining the Case system with the work of their 
inventor, C. A. Hoxie. General Electric engineers, Robinson and 
Marvin, came to Auburn and went over the Case system. They were 
very pleased with it. Stone, however, would not admit the Case sys- 
tem added materially to that of General Electric and no agreement 
was reached. 

Mar. 19, 1926: John Joy, who knew Sponable at Cornell, paid 
a friendly visit to the Case laboratory. Technically, he represented 
Courtland Smith who had just joined the Fox Film Corporation. 
Joy reported concerning the Case talking picture system to Smith 
and the latter requested Case to bring his equipment to New York to 
demonstrate to the Fox people. 

Apr. 8, 1926: Max Mayer (a dealer in theatrical equipment) 
came to Auburn to witness the Case talking pictures. He pro- 
nounced the demonstration to be perfect, but advised Case that a 
feature picture would be necessary to sell the system to a producer. 
Case considered making this. 

May, 1926: Case organized the Zoephone Company to take 
over and handle the Case system of talking pictures. 

Responding to Courtland Smith's suggestion, reproducing appara- 
tus was taken to New York and successful demonstrations given be- 
fore representatives of the Fox company at Parlor B on 10th Avenue, 
at the Nemo Theater, and at William Fox's home in Woodmere. 

302 E. I. SPONABLE Vol 48, No. 4 

Mr. Fox was at first suspicious of the process ; however, a close-up of a 
canary bird singing while perched on the top of its cage seemed to 
convince him that the sound was not a matter of trickery. 

June 8-24, 1926: The reproducing equipment was installed in 
the Fox Film building, 850 Tenth Avenue. Recording equipment 
Was brought from Auburn and about 300,000 feet of test records 
were made in a temporary hair felt studio room partitioned off on 
the large stage of the Fox building. The purpose of these tests 
was to convince Fox of the practicability of making sound pictures 
under studio conditions. The results were entirely successful. 

July 23, 1926: An agreement was reached between Case and Fox 
resulting in the formation of the Fox- Case Corporation. In gen- 
eral, Case turned over all patents and rights in his system of talking 
pictures to the new company (exclusive of amplification, in which 
he had no rights to give). Case agreed to continue his laboratory 
for the purpose of making recording lights, photoelectric cells, and 
for general development purposes. 

[Ed. Note. Parts 3-7 of Mr. Sponable's paper will be published in the next 
issue of the JOURNAL. ] 


1 French patent No. 19,457 (1857). 

2 'Royal Soc. Cat. of Sci. papers, II, p. 123. 

3 Amer. Jour. Sci., 16 (1878), p. 54. 

4 U. S. patent No. 235,199. ' 

5 U. S. patent No. 1,203,190. 

6 U. S. patent No. 341,213. 

7 J. Soc. Mot. Pict. Eng., XVI, 4, p. 405. 

8 U. S. patent No. 356,877. 

9 HAYS: "See and Hear," p. 38. 

10 HAYS: "See and Hear," p. 39. 

11 U. S. patent No. 680,614. 

12 Anal der Phys. (1901), p. 803; Phys. Zeit., 34 (1901), p. 498; RUMMER: 

"Wireless Telephony," p. 36. 

13 British patent No. 19,901 (1903). 

14 British patent No. 4,661 (1903). 

15 British patent No. 1,364 (1904). 

16 U. S. patent No. 788,728. 

17 British patent No. 18,057 (1906). 

* In connection with the early history of sound this work has purposely 
omitted patents relating to sound-on-disk. Anyone interested can find these 
described in the Film Daily beginning February 24, 1929. 


18 HAYS: "See and Hear," p. 40. 

19 U. S. patent No. 841,387. 

20 French patent No. 386,737 (1908). 

21 British patent No. 4,391 (1908). 

22 British patent No. 12,161 (1910). 

23 Swedish patent No. 31,472. 

24 British patent No. 1,532 (1911). 

26 French patent No. 448,757 (1912). 

26 FRANKLIN: "Sound Motion Pictures," p. 5. 

i7 U. S. patent No. 1,473,976. 

28 U. S. patent No. 1,607,480. 

29 British patent No. 20,798 (1914). 

30 U. S. patent No. 1,335,651. 

81 U. S. patent No. 1,522,070 (Reissue No. 16,870}. 

32 U. S. patent Nos. 823,022; 1,275,189; 1,589,139; 1,591,081; 160,566. 

33 VIEWEG AND LOHN: "Der Toewende Film," Jour. Engl. Pub. (1927). 

34 Trans. SMPE, 16 (1923), p. 90. 

35 U. S. patent No. 1,474,695. 

36 Der Sprechende Film Mihaly (1928). 

37 U. S. patent Nos. 1,301,227; 1,316,354. 

38 U. S. patent No. 1,466,750. 

39 Case, Jour. Opt. Soc. (1918). 

40 Trans. SMPE, 16 (1922), p. 62. 

41 U. S. patent No. 1,816,825. 

42 U. S. patent No. 1.605,531. 


W. V. WOLFE** 

Summary. During the war it was not possible to obtain annual progress re- 
ports as has been the custom, and up to the present time it has not been possible to 
obtain progress reports in all fields covering the war period. However, some reports 
have been prepared and are presented here, with the hope that publication of annual 
reports of the Progress Committee may be resumed in 1948. 


Professional 35 Mm (Emulsions). The war years saw intensive 
research and development on three-color films and papers, particu- 
larly of the multilayer type. Concurrently, there was an increas- 
ing demand for color on the screen. 

In 1945, Technicolor Monopack went into extensive production 
use, "Thunderhead", a Twentieth Century-Fox production, being the 
first feature filmed entirely with the three-layer camera film. C. G. 
Clarke described the application of Monopack on this production in a 
paper 1 published in the JOURNAL. 

Also, in 1945, Ansco announced a complement of 35-mm reversible 
color films, Type 755 soft gradation camera film, Type 132 duplicat- 
ing film, and Type 732 printing film. These were described by Duerr 
and Harsh in a paper 2 presented at the October 1945 Technical Con- 
ference. The processing of these films may be done by the studio or 
commercial laboratories on continuous processing machines. 

(a) Development of the negative silver image 

(b) Shortstopping 

(c) Hardening 

(d) Second exposure, with white light 

(e) Color development, with the dyes formed simultaneously 
in the three layers by coupling action between nondiffusing 
dye-formers in the layers and the oxidation products of de- 
veloping the positive silver image 

* Received Feb. 25, 1947. 
** Chairman, 1946. 


(/) Shortstopping 

(g) .Hardening 

(h) Bleaching by reconverting both silver images to halides 

(i) Fixing 

(j) Washing and drying. 

In Europe several features and shorts were produced in Agfacolor, a 
negative-positive three-color process using multilayer films. Reports 
on this process and its application were presented at the October 1945 
and May 1946 Technical Conferences of the Society. 

16-Mm Film. In 1943, Technicolor began production of 16-mm 
three-color imbibition prints with dye soundtracks. Early in 1945, 
Ansco introduced two 16-mm reversible color films, Type 234, 
balanced for tungsten illumination, and Type 235 balanced for day- 
light. The processing of these films is described 3 by Forrest in the 
November 1945 issue of the JOURNAL. 

Nondiffusing color-formers in the emulsion layers couple with oxi- 
dation products of the action of a single developing agent in the sec- 
ond developer to form the three dyes in their respective layers. 

In August 1946, Eastman introduced Type 5268 Kodachrome Com- 
mercial Film 16-mm, designed to provide a low-contrast color original 
from which a color release print of normal contrast can be made on 
Kodachrome Duplicating Film. Type 5268 is balanced for a color 
temperature of 3200 K. 


Films. The trend toward fine-grain recording stocks resulted in 
their universal usage by 1945, following the introduction of Types 
1372 and 1373 by Eastman, and Types 232 and 236 by duPont. Types 

1372 and 1373 are described 4 by Corbin, Simmons and Hyndman 
in the October 1945 issue of the JOURNAL. The 1372 emulsion, de- 
signed for variable-area recording, is characterized by high contract 
and minimum image spread. The latter characteristic permits its use 
for recording direct positive VA tracks. It has sufficient speed to 
record with either unfiltered or UV filtered tungsten. Comparable 
image quality is obtainable with either type of illumination. Type 

1373 is a variable density negative material designed for development 
in a normal picture developer, and has sufficient speed for white-light 
recording. DuPont Type 236 variable-density negative stock was 
designed to fit release negative requirements for white-light printing 

3DB W. V. WOLFE Vol 48, No. 4 

to release positive. It has an inherent low gamma infinity to reduce 
96-cycle flutter and to permit development in picture negative de- 
veloper, and is sufficiently fast to record either low or high gamma 
variable density with white-light exposure. Type 232 is a fine-grain 
sound positive developed to meet the need for a printing material 
which, white-light printed from high gamma VD negatives and proc- 
essed with normal release positive techniques, would yield the de- 
sired over-all contrast. 


Films. Increased activity in television has resulted in require- 
ments for special film stocks. Early in 1946, duPont announced 
two such films, Type 323 Kinescope Recording and Type 136 Gamma 
Pan 2. The former was described by White and Boyer in a paper en- 
titled "A New Film for Photographing Television Monitor Tubes", 
presented at the May 1946 Technical Conference. Type 136 is a 
panchromatic negative, similar in speed and contrast to duPont 126 
Type Superior 2, but differs from the latter in that the upper portion 
of its sensitometric curve has a rising characteristic rather than the 
conventional shoulder. Meschter discussed the considerations lead- 
ing to the design of this product in a paper presented before the May 
1946 Technical Conference, "Television Reproduction from Nega- 


Set Lighting. To meet a demand for a super-powered lighting 
unit to be used where the cinematographer desires to create an 
effect as though all of the light on the set were coming from a single 
source, the Mole-Richardson Company has designed and manufac- 
tured a super-high-intensity carbon-arc lamp known as MR Type 450. 

This unit is a rotating high-intensity type which uses a carbon 
trim consisting of a 16-mm X 22-in. super-high-intensity positive and 
a l7 /32 X 9 in. HD Cored Orotip negative operating at 225 amp and 75 
arc v. 

It is equipped with a 24-in. diameter Fresnel-type condenser lens, 
and the drum is of sufficient size for proper ventilation. The feed 
motor is mounted on the back of the lamp where it is away from the 
heat of the arc. 

In addition to use as a "one-source" lighting unit, this lamp is valu- 
able for shadow effects, for penetrating into deep sets, and for boost- 
ing daylight on exteriors. 


Another unit in the advanced stages of design is a super-high-in- 
tensity spot projector, which will be similar to the Type 450. This 
lamp will be equipped with an integral optical system for throwing a 
well-defined and close-controlled spot for use in follow shots such as 
would be made in a skating picture. 

Process Projection. Mole- Richardson Company has resumed 
production on a special carbon arc process projection lamp house, a 
number of which were manufactured before the war to meet specifi- 
cations set up by the Research Council of the Academy of Motion 
Picture Arts and Sciences. As a result of information gained during 
the production of specialized searchlight equipment during the 
war, and from experience in operating the process lamps previously 
manufactured, the current input contacts for the positive carbon 
and the photronic cell control mechanism have been simplified. 


The end of the war found Britain supporting an efficiently organ- 
ized movement whose sole function was the production of documen- 
tary films sponsored by the Ministry of Information. The movement, 
which in 1939 was an enthusiastic but scarcely fully developed indus- 
try, had advanced from almost an amateur to a professional organi- 
zation of considerable value to the government in its work of informa- 
tion and propaganda. In technical polish, too, the advance was made 
from bare adequacy to frequent brilliance. This last, despite the ap- 
palling shortage of equipment, floor space, and raw stock, and the un- 
certainties of processing and projection conditions. 

With the end of the war and the sweeping change of administra- 
tion from a Coalition to a Socialist government, considerable doubts 
were felt by documentary technicians as to what their future would 
be. Although finance for this type of film could always be relied upon 
for a number of films for major commercial undertakings, this number 
would be nothing like enough to keep all the units fully occupied. 
And, in any case, many documentary workers feel that the advertis- 
ing, no matter how well made, is scarcely the ideal vehicle for their 
particular styles and technique. 

However, these doubts now seem to have been unnecessary. The 
present government, after over a year in office, has shown no signs of 
abating its thirst for cinema material. Films on health information, 
social services, and all forms of education are still being commis- 

308 W. V. WOLFE Vol 48, No. 4 

soned, and even if the tendency of the cinema exhibiting trade to 
close its screens to the official-sponsored film becomes a reality, the 
Central Office of Information, which is the peacetime counterpart 
of the Ministry of Information, has a vast organization for nonthe- 
atrical screenings. In any case, documentary workers in general feel 
that the public taste has been so whetted by this type of film, and the 
ability to blend entertainment with information is now so skillful, 
that commercial distribution in the theaters will still be secured for 
the best of them. 

In Britain, the gap between the production methods of the docu- 
mentary and the feature units, so wide in 1939, has closed appreciably. 
The feature units have made pictures on documentary lines of realism 
using natural artistes and actual settings while the documentary 
movement has frequently moved into the studio's sound stage with 
the professional actor. Perhaps in this country more than in any 
other have the two paths drawn together. Not only that, but our 
ideas have been broadened by seeing many of the magnificent docu- 
mentary films from the American Office of War Information. We 
have learned a great deal from films like "Fighting Lady" and the 
"Why We Fight" series. And we like to think that perhaps we have 
contributed some ideas to America with films like "London Can Take 
It", "Target for Tonight", and "Desert Victory", while neither of us 
will forget the wonderful Anglo-American collaboration that gave 
us "True Glory". 

The great difficulty, now as always, is technical equipment, particu- 
larly in the field of sound recording. The majority of the units 
producing documentary films do not carry recording equipment, and 
rely for their sound tracks upon the very few organizations that do. 
With the exception of one or two of the nonroyalty recording studios, 
there are two units which are doing the bulk of all recording necessary 
for Central Office of Information films. They are the COI's own pro- 
duction unit, the Crown Film Unit, which will be headquartered at 
Beaconsfield Studios operating with RCA equipment, and Merton 
Park Studios using Western Electric. During the war, it was fre- 
quently possible to make use of recording facilities at the larger 
feature studios, but these are now more or less fully occupied making 
the films for which they were intended, and little time is left for other 

The units which were maintained during the war by the fighting 
.services have now largely been disbanded. Their personnel on 


demobilization have been reabsorbed into the industry in civilian ca- 
pacity, both in documentary and in feature work, and some of their 
equipment has come the way of the documentary movement. In par- 
ticular the RCA channel, used during the latter years of the war by 
the Royal Naval Film Unit, has been transferred to the Crown Film 
Unit where it is helping enormously to keep up the flow of production. 
New equipment from the United States is coming in slowly, but the 
Board of Trade is naturally more ready to grant import licenses to or- 
ganizations capable, or at least potentially capable, of exporting films 
in exchange for foreign currency. Further, we in this needy country 
do not always realize that the Hollywood industry is presumably 
making big claims on American production after the supply difficulties 
of wartime. There are indications that a considerable amount of 
motion picture equipment will be manufactured in thiscountry eventu- 
ally, but in Britain as everywhere else, it takes a long time to re- 
cover from six years of war, and to develop and produce a regular flow 
of highly specialized machinery. 

While comparatively few changes have taken place during these 
years in the type of sound and camera equipment at our disposal, 
nevertheless we have progressed in our methods. The RCA PM 45 
portable recording channel made its British debut with the Crown 
Film Unit, and its compactness has made it possible for us to record 
direct sound on the type of location loved by documentary directors, 
obtaining the benefits of automatic volume compression not available 
in the earlier model, so invaluable when trying to cope with "natural" 
untrained voices. The few Mitchell cameras possessed by the makers 
of short films are above reproach, although tremendous use is still 
made of the light-weight "wild" camera manufactured over here by 
Newman and Sinclair. We are also learning, or rather our sound en- 
gineers are beginning to teach our directors, that the post-synchro- 
nized sound track, when properly done, can be cheap, very easy and 
most convincing. Some of our technicians have paid brief visits to 
Hollywood where they learned many things, and our films are begin- 
ning to profit by their lessons. 

Class "A" push-pull recording is beginning to trickle into documen- 
tary studio work, and the laboratories seem to have overcome most of 
their initial troubles with fine-grain positive stock. Fine-grain emul- 
sions for recording negatives are now being manufactured over here, 
but at the moment of writing are being avoided until full research 
with the laboratories has been finished. The 200-mil push-pull track 

310 W. V. WOLFE Vol 48, No. 4 

for variable-density work is still only a projected feature of the major 

An interesting development during the past month or so has been 
the formation of the British Broadcasting Corporation's Television 
Film Unit. It is beginning modestly, but has already made its mark 
by producing and broadcasting its own film of the Victory Day cele- 
brations in a very few hours. Indeed, the film was transmitted from 
the Alexandra Palace transmitting station on the evening of Victory 
Day, June 8. There would appear to be room in the future for a lively 
and profitable collaboration between the Television unit and the 
other documentary groups. 

As might be expected with a movement which depends for so 
many of its screenings upon the purely nontheatrical show, we have 
suffered, and are still suffering, from acute 16-mm troubles. The 
enormous demand for this type of film tended completely to swamp 
the laboratories, and inevitably processing suffered. This factor, 
coupled with the relatively inefficient projectors in use throughout 
the war, and all the other problems of acoustics and so on, gave the 
substandard film show a richly deserved bad name. And, unfortu- 
nately, this country's efforts to overcome these problems have not had 
the enthusiasm behind them, and certainly not the successful results, 
that have attended similar situations in the U.S.A. 

The country is just now going through a form of 16-mm revival. 
Commercial distributors have indicated their intention of releasing 
substandard copies of their feature films; miniature movie houses 
have appeared in many towns, and in many other ways the 16-mm 
cinema is being brought before the public in so determined a fashion 
that it is becoming regarded even more rapidly than during the war 
as something other than a toy. All this is bound to help the efforts of 
those who have tried, so far in vain, to point out that a casually per- 
formed optical reduction print from a doubtful release copy is scarcely 
the most efficient way of providing material for the education and in- 
struction of those whose only approach to the cinema is by way of the 
miniature projector and the village hall. 

The Crown Film Unit, with which the writer is actively connected, 
has before it a period of intense interest and development. Through- 
out the past four years, it has worked in the Government-requisi- 
tioned studios at Pinewood. These are the most modern studios in 
operation in the country. They are blessed with all the elaborate 
refinements necessary for the production of major feature films, and, 


for England at any rate, are very large. In these respects, Pine wood 
is completely unlike anything that the documentary movement has 
ever been accustomed to, or is ever likely to enjoy in the future. 

The studios have now generally been de-requisitioned, and with 
the exception of one stage and the bare minimum of other space left 
to the Unit pending the transfer to its new home, they are back on the 
job of normal production. The documentary movement is thus in 
the unenviable position of being the unwanted guest, and this position 
will continue until the beginning of 1947. 

The Unit then moves to Beaconsfield studios, which at the time of 
writing are being transformed from their wartime status as a muni- 
tions factory back to a studio a complicated and laborious operation. 
There will be one medium-sized stage, plenty of cutting rooms and 
vaults, and two theaters. Of the latter, one will be devoted entirely 
to the processes involved in sound recording, and will be large enough 
for small orchestral work. Its interior will be fitted with the latest 
ideas in policylindrical surfaces, reverberation chamber, and rerecord- 
ing from seven tracks, and should be admirably suited for the work 
it has to perform. The Unit will be provided with three RCA record- 
ing channels mounted on trucks, two of which are the standard studio 
model and may be patched through to the theater for rerecording 
work or to the stage for normal shooting. The third is the PM 45 
portable channel aleady referred to. All three will be capable of 
producing the standard or the Class "A" push-pull track. It is hoped 
in time to reopen the laboratory attached to the studio, but the fact 
has been accepted that this must remain a long-term project. The 
Unit is not falling into the mistake of thinking that a laboratory can 
perform first-class work without many months of experiment and 
"settling down". 

A rear projection process plant is to be installed in the new studio. 
The equipment we intend to use was constructed during the war for 
the Royal Air Force Film Production Unit, and extensive use of it 
will reduce many of the problems of actual "on-the-spot" shooting, 
characteristic of this type of film. We hope that it will not reduce the 
reputation for authenticity gained by the Unit's productions in the 

Finally, at Beaconsfield will be housed the Central Film Library, 
the organization responsible for ordering and dispatching copies of 
COI films to where they are to be screened. There is room for expan- 
sion at Beaconsfield, and while at first it will accommodate purely 

312 W. V. WOLFE Vol 48, No. 4 

the production nucleus of the Crown Film Unit, in time it may well 
prove to be one of the main centers of the European documentary film 


British feature film production as we know it today has had to face 
up to many trials and difficulties, including two world wars. But 
whereas during World War I production practically ceased, World 
War II saw the plans laid and even developed for it to become a major 
British industry. 

In 1938, the number of feature films made in Britain and regis- 
tered with the Board of Trade was well over two hundred. However, 
judged by American standards, a large number of these were of poor 
quality a fact which discerning British cinema audiences were quick 
to detect when viewed alongside the American product. This state 
of affairs could not long continue, and as a result of the new Quota 
Act coupled with the financial crisis greatly influenced by the turn 
of European events, about 100 feature films (or less than half those 
registered in the previous year) were made in 1939. During this year, 
British feature production was at the crossroads and with the threat 
of war, the freezing of capital and the general low standard, every- 
thing pointed to a very rapid decline and possible extinction. 

With the outbreak of war and the probability of large-scale air 
raids, it was obvious that war industries would have to be expanded 
and dispersed. Studios, mostly situated on the outskirts of London, 
were ideal places for requisitioning by the Government, particularly 
as the industry had slumped and some studios were not in production . 
For instance, Amalgamated Studios (now owned by MGM) at Bore- 
ham \Vood, with a floor space of over 150,000 sq ft, although com- 
pleted long before the outbreak of war, had never been opened. So 
this studio with four stages, Pinewood (five stages, 70,000 sq ft), 
Sound City (six stages, 50,000 sq ft), ABPC (four stages, 60,000 
sq ft), Beaconsfield (one stage, 7000 sq ft), MP (two stages, 15,000 
sq ft), Wembley (two stages, 10,000 sq ft), Worton Hall (three stages, 
20,000 sq ft), and Nettlefold (two stages, 15,000 sq ft) were among 
those to be requisitioned, while Denham had one of its large stages 
used for food storage. Pinewood and Wembley were given to the 
Service and Crown Film Units which, of course, were built up and ex- 
panded rapidly throughout the war years. This left eight studios or 
about thirty stages free where feature films might be made. 


During the first uneasy lull of the first eight months of war the 
"phoney war", as it was called it was realized that entertainment 
had to be provided for the people and Armed Services. Encouraged 
by official statements and steadily growing box-office receipts, fi- 
nance became available and over sixty feature films were produced in 
1941. However, this output was not maintained in 1942 with only 
45 features produced. Shortage of material, declining manpower, 
damage to Studios, and loss of production time because of air raids, 
all had their effect. When the air raids were intense it was not unu- 
sual for production crews to have to take cover half a dozen times a 
day, particularly at those studios nearest to Central London. Each 
period of "alert" lasted any time up to an hour, and during the win- 
ter months personnel were anxious to get home as soon as possible 
after black-out to avoid the dangers of traveling across London dur- 
ing a raid. In the mornings, lateness on the set was often unavoidable 
because of railroad dislocation from the previous night's raid. It is 
to be wondered how such a "luxury" industry could survive under 
such conditions. But survive it did and what is more, it flourished 

Several British features some on war subjects appeared which 
had a sincerity and authenticity far superior to the American product 
arriving in Britain. British cinema audiences were quick to recognize 
this, as they had first-hand knowledge of such situations presented on 
the screen: Instead of the isolated British feature being praised by 
critics and audiences alike, a new standard was gradually but surely 
being set up throughout the whole industry and more and more fea- 
tures received approbation. Naturally, the cry was for more and bet- 
ter British features ; but, although the standard increased each year, 
the number remained around seventy for 1943 to '45. With its lack of 
organization compared with the American industry, gradual deterior- 
ation of equipment through little or no replacements, together with 
the difficulties already mentioned, British feature production had 
reached its wartime peak with the amount of manpower and number 
of studios available. Over a third of the prewar technicians in the in- 
dustry were in the Armed Services and nearly a quarter of those who 
entered the industry after the outbreak of war had been drafted also. 

The British industry had gradually broadened the canvas of its 
production notably with "Henry V" and "Caesar and Cleopatra", 
both made, like many other features, under extreme difficulties. 

So the war came to an end with British features comparing favor- 

314 W. V. WOLFE Vol 48, No. 4 

ably and in many cases out-grossing their American counterparts. 
During the war, new British stars had been built up and these, with 
those already established, had a drawing power equal to many in the 
Hollywood constellation. 

The immediate need was for the speedy de-requisitioning of those 
studios occupied for war purposes and the repair of those damaged 
by air raids and F-bombs. Practically all studios had received dam- 
age chiefly from blast and a few cases from incendiary, but many had 
been temporarily repaired. Teddington (Warner Bros.) had unfor- 
tunately received a direct hit by a fly-bomb and was completely out 
of action. Denham had scores of offices and the dubbing and scoring 
stage destroyed by incendiary bombs, but permission was given to re- 
build the latter and so it was kept in production throughout the war. 
Shepherds Bush likewise was extensively damaged by incendiary but 
kept in production. 

By the middle of 1946 most of the requisitioned studios had been 
released. Naturally, many months were needed before production 
could start on its former scale. Structural alterations were needed in 
some cases and equipment required a complete overhaul. The po- 
sition today is that most of the studios released are already in re- 
stricted production and by the end of 1946 all the necessary repairs 
and reconstruction will have been completed. The rehabilitation of 
studios has been relatively slow despite the Government's interest in 
and support of the industry. Shortage of materials and 'manpower 
are the principal reasons for this slowness, efforts being concentrated 
on the repair and construction of houses which receive first priority. 

Although the future looks bright, the expansion of the industry de- 
pends upon construction of new stages, the delivery of new equipment, 
and the training of additional personnel. Work has already started 
on the reconstruction of ABPC, MGM, and Teddington Studios. 
Production should start there during 1947. Both Paramount and 
Twentieth Century-Fox have announced building programs, but it 
will be some considerable time before these projects are started. Most 
of the existing studios are planning or have already planned extensions 
to their lots and are now awaiting Government licenses to build. 

The industry is desperately short of all kinds of equipment. Much 
of the existing equipment is obsolete and modern replacements are 
being delivered very slowly too slowly to meet the demands. New 
cameras, sound booms, and light equipment are being manufactured, 
but the supply of recording and rerecording equipment particularly 


that of American manufacture is very inadequate. British manu- 
facturers are doing their best to meet the situation but are faced with 
shortage of materials and labor. 

Although the majority of the technicians in the Armed Services 
have been demobilized, shortage of skilled personnel is still acute. 
The position is improving slowly and fortunately the industry can call 
upon many ex-Service people who learned technical jobs in the vari- 
ous film units during the war and who may wish to enter the film in- 
dustry upon their return to civilian life. 

About seventy sound stages should be available for feature produc- 
tion when all the existing plans are completed. The immediate ob- 
jective is to produce 200 features per year. To attain this, the indus- 
try must become much more efficiently organized, and more and bet- 
ter equipment must be given to the technicians. If the industry is to 
prosper, schedules and costs must be drastically reduced. 

A golden opportunity presents itself for the future of feature pro- 
duction in Britian today and, given the necessary facilities, nothing 
should prevent it reaching a peak undreamed of only a few years ago. 


In 1941 there were in Mexico two principal motion picture studios, 
Clasa and Azteca. These studios provided 17 stages. There were 
three licensed production recording channels, one combination scor- 
ing and rerecording channel, and also about six locally made recording 
channels. Both Clasa and Azteca had laboratories, but the Azteca 
laboratory was operated on a ''rack and tank" basis. There were no 
facilities for handling color pictures and in general the feature pic- 
tures being made were of the low-budget variety. 

About 35 such features were made during 1941 . By the fall of 1946 
there were five major studios in operation : Clasa, Azteca, General 
Cinematographico, Churubusco, and Tepeyac. These studios pro- 
vided 61 stages with eight additional stages under construction. 
There were also two studios under construction but not yet in opera- 
tion Stahl and Quotemoc each of these studios will consist of four 
stages. There were 32 licensed production recording channels and five 
rerecording and scoring channels. 

Each of the studios now in operation includes a machine laboratory. 
A limited amount of color work is being done on the bipack principle. 
During 1945 about 100 features were made but during 1946 only about 
50 features will be made. Although the number of features has 

316 W. V. WOLFE 

increased very little compared to the increase in production facilities, 
features now being produced are of a much higher caliber than those 
produced prior to the war. 


1 CLARKE, CHARLES G.: "Practical Utilization of Monopack Film", /. Soc. 
Mot. Pict. Eng., Nov. 1945, 45, p. 327. 

2 DUERR, H. H., AND HARSH, H. C.: "Ansco Color for Professional Motion 
Pictures", /. Soc. Mot. Pict. Eng., 46, 5 (May 1946), p. 357. 

3 FORREST, J. L. : "The Machine Processing of 16-Mm Ansco Color Film", 
/. Soc. Mot. Pict. Eng., 45, 5 (Nov. 1945), p. 313. 

4 CORBIN, R. M., SIMMONS, N. L., AND HYNDMAN, D. E. : "Two New Eastman 
Fine-Grain Sound Recording Films", /. Soc. Mot. Pict. Eng., 45, 4 (Oct. 1945), 
p. 265. 




Summary. The history of post-synchronization as a technique is briefly de- 
scribed, with special reference to its use in the process of language conversion. The 
means by which the illusion of acoustic perspective is obtained within the confines of 
a limited stage are described. 

Post-synchronization is a term which originally described a form of 
salvage operation in sound motion pictures. The technique has 
been developed and its uses expanded to such an extent that today 
the post-synchronization process often becomes an integrated and 
almost independent phase of motion picture production. 

The process is essentially one of making a dialogue and effects 
record to synchronize precisely with the lip movements and action 
of an already existing picture. 

The technique grew very understandably out of a desire to salvage 
the dominant value of a scene or sequence in a picture for which the 
original synchronously recorded sound was defective. In a majority 
of such instances the original sound was defective because of pictorial 
requirements which demanded locations in which even adequate 
sound recording could not be accomplished. In recent years the 
density of air traffic over Southern California has tentatively put 
almost any exterior location into this category. 

As the post-synchronization technique developed to the point 
where its intervention was undetectable in the final product, an 
undeniable further liberty became available in the choice of pictorial 
situation. Although a sound record is usually made in even the most 
extreme of these locations, it is recorded to serve simply as a trans- 
cript of what was said as a helpful tool in the later post-synchroniza- 
tion process. 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** MGM International Films Corporation, New York. 


318 T. LAWRENCE Vol 48, No. 4 

Most producers of entertainment films derive from thirty to forty 
per cent of their grpss revenues from the exhibition of their product 
in territory outside of the United States. The continuance of this 
foreign revenue plays a dominant part in the profitable operation of 
any American film company. This pattern of income in the main 
held true even before the introduction of sound motion pictures. The 
initial adverse influence of this development in the medium on receipts 
from abroad was largely lost sight of in the light of the enormous 
success it enjoyed in the domestic market. 

After a lag of about two years behind domestic theater sound in- 
stallation, important numbers of theaters abroad were prepared to 
play sound motion pictures. American producers were now con- 
fronted with the problem of competing with foreign-made pictures 
on an entirely new basis. That same attraction of novelty which so 
beguiled American audiences into a profitable attendance at almost 
any "all-talking" picture in the early years of sound operated now 
to the profit of foreign producers, who delightedly discovered that 
their own nationals actually preferred to hear and to see a mediocre 
picture in the language of their own country to a good film which, 
in the large, they could not understand. 

The first American reaction to this problem was the introduction of 
superimposed titles. By this device foreign audiences were provided 
with a truncated printed translation of the English dialogue, and 
thereby were enabled to follow the story. Although this method 
bridged the competitive gap between the average foreign picture 
playing to its native audience and the basically more attractive 
American film, it demanded a concentration on reading matter by 
those of the audience who did not understand the original English 
and introduced an inevitable distraction to those who did. 

This state of affairs had not gone on for very long before it occurred 
to a good many people technically involved with motion pictures 
that the post-synchronization technique already existing might sat- 
isfactorily be extended to include language conversion. 

The extension of the post-synchronization technique to the vast 
new field of .language conversion of course involved, first of all, the 
basic necessity of providing a complete new script of dialogue in a 
foreign language which would not only match its English prototype in 
general syllabic conformation and special labial movement, but in its 
very spirit and character as well. Certain mechanical devices were 
developed to make graphic to the translator the type and duration of 


salient sounds in the original dialogue and, by extension, to provide 
the ultimate re-enacting actors with an indication of the beginning, 
duration, and end of each word they were to speak. These devices, 
though they undoubtedly accomplished the specific things they were 
designed to do, were also inclined to produce a stultifying effect on 
both the translator's imagination and the actor's interpretation. 
MGM International Films and certain other American companies 
have found it advantageous to the over-all quality of their product 
to dispense completely with these mechanical aids and to substitute 
for them more time and greater effort in script preparation and re- 
hearsal. We believe that this latter approach more than justifies its 
greater cost. The detailed problems of translation and casting have 
been previously described in considerable detail and I shall speak no 
more of them here. 

By whichever means arrived at, the actors and their script even- 
tually come together on a synchronization stage. This is where the 
ultimate illusion must be created and there are two people working 
together to do it : the director and the sound mixer. 

The mixer in this situation, in contrast to his predecessor on the 
set of the original production, is in a position to suffer from an almost 
complete lack of imposed conditions. He is in the unhappy position 
of having, himself, continuously to set up bigger and better hurdles 
for himself to jump over. There would be nothing easier' than for 
him to set up a microphone in an ideal position, with all the actors 
grouped obligingly in front of it, and then, after the director had 
achieved a satisfactory excellence of performance and synchronization 
from the cast, make a flawless recording. It would seem, offhand, 
that everything is in his favor. He is alone on a nice quiet stage with 
the director and a few actors ; no cameraman to complain about the 
mike being in the picture or casting shadows; no annoying sound 
reflections from the walls of peculiarly shaped sets. The actors have 
an amiable tendency to stay approximately where they are put. It 
would seem to be a perfect setup, except that the result, when later 
seen with the picture, would be bad. All of the tangibles would 
seem to be there; proper casting, performance, synchronization. 
Everything except the illusion of reality that the original conveyed. 

The missing elements, whose lack has robbed the synchronized 
version of the illusion of the original, are perspective (or rather, 
changes in perspective), with the variations in voice effort which 
should accompany such changes. 

320 T. LAWRENCE Vol 48, No. 4 

It is to supply these missing factors in the illusion that drives the 
synchronization mixer to a constant exercise of his imagination. To 
do this, he has at hand a small collection of basic tools. These con- 
sist of a studio of moderate size and low reverberation time, a few 
hard-surfaced panels with which he may modify that reverberation 
time, two or three small straight-backed chairs to serve as barriers 
for actor movement, and three or fewer microphones. It is not a 
particularly impressive array with which to re-create the enormous 
acoustic ambiance of the original. As a matter of fact, it can not be 
done, it can only be made to seem to have been done! And drama- 
tically speaking and for the purpose of the ultimate illusion, no more 
need be required. 

In effect, the mixer is required to provide the impression of an 
almost unlimited range of reverberation characteristics while oper- 
ating, actually, within relatively circumscribed limits. To achieve 
this impression successfully requires a careful deployment of forces. 
Before the first post-synchronized scene is recorded, the mixer must 
have clearly in his mind the exact range of acoustic conditions in that 
particular picture which he is going to have to simulate. Even more 
important, for his purposes, is the sequence in which such changing 
conditions occur. It is difficult to explain this without examples, 
but hypothetical ones will do. 

Let us; for example, assume that a sequence of settings occurs in 
the following order: (A) a large entrance hall, (B) a drawing room, 
(C) a dining room, (D) a long corridor, (E) a bedroom, and (F) a 

It is proper to assume that settings (A) (the hall), (D) (the corridor), 
and (.F)(the bathroom), should be more reverberant in character 
than the other three. There is no obvious reason why the remaining 
three locations the drawing room, the dining room, and the bed- 
room should differ acoustically among themselves and it is quite 
possible that there is no detectable difference among them in the 
original recording. Since, however, it is an important thing in the 
illusion to supply an acoustic change to accompany each visual one, 
settings (B) and (C), which adjoin, should be treated differently 
acoustically. The absolute value of reverberation present is of much 
less importance in general than its contrast with what immediately 
precedes and succeeds it. 

The present example, if there were no other reason to dictate length, 
would be broken down into a minimum of three scenes. The first 


two settings could be shot together with the studio set up in its more 
reverberant condition. The necessary differentiation between the 
entrance hall and the drawing room would be accomplished in the 
first instance by exaggerating microphone distance relative to the 
apparent visual placement of the speaking characters, and in the 
second case by compressing it. 

The second group of three settings could be shot together with the 
studio set up in an intermediate reverberant condition. The dining 
room set might be shot with microphone distances in a "normal" re- 
lationship with apparent visual placement; in the corridor, micro- 
phone distances would again become exaggerated; and in the bed- 
room, compressed. 

The bathroom would need a treatment all its own a tight boxing- 
in with reflecting panels. 

Should these same sets occur in a different sequence, say in the 
order (D), (A), (B), (C), (E), they would undoubtedly be shot in two 
groups: (X>) (the corridor) and (A) (the entrance hall) in a rever- 
berant studio condition, and (B) (the drawing room), (C)(the dining 
room), and ()(the bedroom) in a moderately reverberant condition. 
Thus in all cases the set requiring the most reverberant condition is 
shot on a "bright" stage, and the one requiring the least reverbera- 
tion is shot on a relatively "dead" stage, all those falling between can 
be satisfactorily controlled by microphone placement. 

Except in extreme cases where a really dramatic effect is required 
to be made by acoustic means, the usual set need have no absolute 
reverberation characteristic. It is sufficient, in its post-synchronized 
re-creation, that it conform with the actual only in very general and 
relative terms. It is much more important, for example, in the case 
of two such generally comparable acoustic structures as a living 
room and bedroom in immediate sequence, that they should be made 
to differ from each other at the cut between them rather than that 
any very serious effort be made to maintain an absolute acoustic 
quality associated with an individual set whenever it may occur 
throughout a picture. There are, however, the inevitable exceptions. 
There occasionally occur sets which have associated with them ex- 
treme and therefore memorable acoustic characteristics. Since such 
occurences are deliberate and serve a definite dramatic purpose, a 
definite and recognizable acoustic characteristic must be established 
for such a set and carefully maintained. 

It has already been pointed out that the post-synchronization 

322 T. LAWRENCE Vol 48, No. 4 

mixer is singularly free from externally imposed conditions on his 
microphone placement. This gives him one important advantage 
in the enhancement of the apparent acoustic range through which he 
can operate. He is in a position to shoot an extreme close-up with a 
much closer microphone placement than would be physically possible 
on the original set. This sounds like something very minor, but it is 
one additional position added to a technique which is greatly con- 
cerned with the acoustic illusion of position. 

There is a further extremely valuable tool to employ in the simula- 
tion of an acoustic ambiance. Unfortunately, for its more active 
employment, it demands a remarkable degree of co-operation among 
the mixer, the director, and the actors. This is the matter of using 
to the greatest possible advantage the voice effort energy distribution 
characteristic. To inflict yet another hypothetical example, let us 
assume just one more arbitrary situation. A fully modulated re- 
cording of an actor speaking in a moderate volume of voice, at, say, 
six feet from a microphone in an average studio, will, when reproduced 
at normal volume, suggest a very definite combination of position and 
room characteristic. That same actor speaking loudly, all other 
conditions being held constant and no attempt being made to in- 
crease the reproduced volume, will appear to have receded consider- 
ably in position and to be speaking in a "deader" enclosure. It is 
only by the employment of this device that it is possible to obtain an 
acceptable illusion of voices in exteriors, even though recorded in the 
"deadest" commercially practicable studio. 

Since vocal performances of any musical importance are almost 
invariably prerecorded in current production practice, there can be 
little, if any, attempt made to match sound pickup to picture. Al- 
though a great deal of dramatic license is permissible in this respect, 
there is no denying that in the post-synchronization of such material 
in a new language the mixer enjoys an invaluable assistance : he at 
least is certain of what the picture looks like and it helps enormously. 

The rerecording of a post-synchronized film is, in all essentials, the 
same process as was gone through for the original version. Some 
companies, and in particular MGM, operate several synchronization 
studios, each synchronizing in the language of the country in which 
it is located. In the interest of simplification of both the rerecording 
process and the transshipment of film, a certain consolidation of the 
original rerecording material is effected. The original music tracks, 
of which there may have been several per reel, are premixed with 


effects to provide a basic museffex track for foreign rerecording. 
Sustained crowd noises are supplied separately since they will ul- 
timately be bolstered by similar tracks of foreign origin and the proper 
balance for the premix, therefore, cannot properly be predetermined. 
The ultimate result the release print of a post-synchronized 
film is an integrated whole, betraying little, if anything, of the con- 
version process through which it has passed. The only thing it will 
not do is to serve in its old incidental role: a teacher of "English 
Without Tears". 


MR. J.I. CRABTREE : How closely does a post-synchronized language film com- 
pare with one originally acted with, say, natural actors just speaking the native 

MR. LAWRENCE : It is quite possible to watch the picture for a considerable per- 
iod of time and never realize anything has been done to it. The illusion is vir- 
tually complete. 

MR. CRABTREE: I am very surprised at this. Many years ago, at one of our 
conventions, a picture was shown in which the synchronization was remarkable. 
Then for some reason all the companies dropped this synchronization, and now I 
am very surprised that it has reached the stage that it has. Apparently there is 
quite a lot of it going on. Could you give us some idea as to how much of this is 
being done now? 

MR. LAWRENCE : Before the war most of the principal American companies 
were synchronizing in foreign languages, and owing to restrictive regulations 
abroad most of the synchronization had to be done abroad. The war, of course, 
was the reason why it was stopped. At the present time, Metro is synchronizing 
every picture which is released in South America. They are beginning again to 
apply the same practice to those pictures which are released in France, and it 
will undoubtedly extend considerably to other parts of the world. 

MR. WOLFE : Has any work been done for China? 

MR. LAWRENCE: About five months ago Metro-Gold wyn-Mayer started 
what might be called an interim method of providing language versions other 
than the principal ones. That is being called the narrated film, in which the 
English dialogue is retained and a narrator in the foreign language explains what 
the action is all about at appropriate intervals. It is, we think, superior to super- 
imposed titles, inasmuch as the distractive effect of the titles on the picture 
is not there. This is being done at present in Chinese, Arabic, Hindustani, and 
Portuguese with some Siamese. 



Summary. The concentrated arc is a new type of lamp whose radiation emitting 
source is a thin film of molten zirconium and a cloud of excited and ionized zirconium 
vapor and argon gas which forms on and very close to the end of the specially prepared 
negative electrode. By modulating the lamp current, the radiation may be modulated 
at audiofrequencies. 

The continuous radiation from the molten zirconium can be only partly modulated, 
the per cent modulation decreasing with increase in modulating frequency and 
in spectral wavelength. The line radiation from the cathode- glow region close to the 
electrode modulates almost completely at all audio frequencies. It is particularly 
strong in the near -ultraviolet and infrared. 

By using suitable modulator circuits, which are adapted to the rather unusual 
impedance characteristics of these lamps, and by using optical filters to select the 
spectral region used, the light output may be made to follow the lamp current modu- 
lation with good fidelity. 

During the war, information about concentrated-arc lamps was 
restricted for security reasons. After the war, security restrictions 
were at first only partly removed so that the original public announce- 
ment of the lamps 1 ' 2 could refer only to their static characteristics 
and the lamps were discussed as simple light sources. Now, all re- 
strictions have been removed, so the dynamic or modulation char- 
acteristics of the lamps may be disclosed. 

Western Union's concentrated-arc lamps are made in sizes ranging 
from 2 to 100 w. The smallest, or 2-w lamp, is the most satisfactory 
for modulation purposes because of its very small source diameter, 
only 0.003 in., its high brightness, about 100 candles per sq mm, and 
its superior modulation characteristics. The larger wattage lamps 
can be modulated, and they will give many more lumens of modulated 
radiation than the 2-w size, but their light can be less completely modu- 
lated ; their modulated light output is less constant with frequency, 

* Presented, Oct. 23, 1946, at the SMPE Convention in Hollywood. 
** The Western Union Telegraph Company, Electronics Division, Water Mill, 
N. Y. 


and their modulated intensity or brightness is less than that of the 
2-w lamp. For applications where a high intensity rather than a 
large quantity of modulated radiation is required, the 2-w lamp is 
superior. Large lamps are finding their major application in photo- 
graphic enlarging, photomicrography, spot lighting, and projection. 

The lamps are made* with the two arc electrodes permanently 
sealed into a glass bulb which is filled with argon gas. The cathode 
or negative electrode is made by packing zirconium oxide into a tan- 
talum or molybdenum tube. The positive electrode or anode is a 
simple plate of molybdenum with a hole in the center, through which 
the light coming from the end of the cathode can pass. After the 
lamps have been evacuated, the bulbs are filled with argon to almost 
atmospheric pressure, and the lamps are processed or "formed". In 
this process the exposed oxide surface at the end of the cathode tube is 
converted to metallic zirconium. When the lamp is operating, this 
extremely thin layer of zirconium metal is melted and maintained as 
an incandescent pool by the intense argon ion bombardment of the 
arc. Most of the visible radiation of the lamp conies from this white- 
hot surface. It has a continuous spectral distribution of the black 
body type peaking near 10,000 A. 

Directly above this zirconium film is a layer of excited and ionized 
zirconium vapor and argon gas in the cathode-glow region of the arc. 
This layer extends for only a few thousandths of an inch from the 
cathode. The radiation from this region is very intense and shows 
three principle spectra, a continuum reaching from the ultraviolet to 
about 5000 A, and the line spectra of zirconium and argon. The 
majority of these zirconium lines occur at wavelengths shorter than 
4500 A, peaking around 3500 A. Strong argon lines are scattered 
throughout the spectrum, the strongest occurring in the near-in- 
frared around 8115 A. The continuous radiation from the cathode 
surface and the continuum and line radiation from the cathode-glow 
region combine to produce the complete spectral distribution char- 
acteristic of concentrated-arc lamps. 

When the current through the lamps is changed or varied slowly, 
the candlepower of all of the various sizes of lamps changes in almost 
exact proportion and the modulation ratio is nearly 100 per cent. 
Modulation ratio is defined as the ratio of the per cent candle-power 
change to the per cent current change which produced it. The linear 

* [Ed. Note. See references for more detailed description of lamp construction. ] 



relationship and high modulation ratio are not maintained exactly as 
the frequency of the current variation is increased into the audio fre- 
quency range. 

That part of the radiation which comes from the incandescent 
cathode surface shows a rapid decrease in modulation ratio with 
increase in frequency and with increase in spectral wavelength. 
Thus, measurements made in the continuum of a 100-w lamp at 
3500 A in the ultraviolet show per cent modulation ratios of 78 at 





FIG. 1. Spectral distribution of the modulated radiation of a 100-w argon- 
filled concentrated-arc lamp! 

200 cycles, 44 at 1000 cycles, and 18 at 5000 cycles. In the infrared 
part of the spectrum at 9000 A, modulation ratios drop to 33 at 200 
cycles, 8 at 1000 cycles, and practically zero at 5000 cycles. 

The radiation from the gas and vapor cloud, of the cathode-glow 
region of the arc, can be almost completely modulated. It shows a 
modulation ratio of 85 per cent or better, a factor which holds for all 
audio frequencies and for line radiation in all parts of the spectral 
range. The spectral distribution of the modulated portion of the 
total radiant energy of a 100-w concentrated-arc lamp when modu- 
lated at 0, 200, 1000, and 5000 cps is shown by the curves of Fig. 1. 



These curves show that, as the mpdulating frequency is increased, the 
amplitude of the continuum, in any spectral region, decreases by a 
much larger factor than the amplitude of the lines. Also, the modu- 
lation ratio appears to be more favorable in the ultraviolet and blue 
end of the spectrum. 

That such is actually the case, for a 2-w lamp, is shown by Fig. 2 
which plots the average per cent modulation ratio, in spectral bands 
0.1 micron or 1000 A wide, at a 1000-cycle modulating frequency . This 
shows that, in the ultraviolet, ratios of better than 80 per cent may 

.7 .8 .9 

FIG. 2. Average per cent modulation ratios in spectral 
bands for a 2-w concentrated-arc lamp modulated 100 per cent at 

be obtained while, in the infrared, values drop to less than 20 per 
cent. The flat portion of the characteristic at around 0.8 micron re- 
sults from the strong argon gas lines, with their high modulation 
ratios, which occur in this region. The strong downward trend is 
caused by the modulation characteristic of the continuum. 

The radiant output of the lamps is so much greater in the infrared 
that there is actually more modulated radiation given off in the longer 
wavelengths than in the ultraviolet, but its degree of modulation is 
less complete. The choice of which spectral region is to be used will 
depend upon which factor, quantity or quality, is the most important 
for the particular application. 



In many cases the part of the spectrum employed will be deter- 
mined by the spectral sensitivity of the receiving device. Thus, if a 
red-sensitive caesium-silver-oxide type of photoelectric cell is used 
to measure the modulated light coming from a concentrated-arc lamp, 
the system will exhibit an entirely different over-all frequency -light 
characteristic than it would if a blue-sensitive antimony type of 
photocell or an ultraviolet-sensitive photographic film is employed. 
Optical filters can be used to further select or restrict the spectral 
region covered. 

FIG. 3. Frequency characteristic for 2-w concentrated-arc lamp 
taken with a caesium phototube. 

The effect on the over-all modulation ratios of systems using these 
two different types of photoelectric cells is shown by the figures of 
Table 1. This shows, for example, that a 2-w argon-filled lamp, 


Per Cent Modulation Ratios at 75 Per Cent Current Modulation 








Antimony Cell (Freq.) 

Caesium Cell (Freq.) 





































April 1947 



75 per cent current modulated, if measured with an antimony-type 
photocell, will show a modulation ratio of 76 per cent at 200 cycles, 
63 per cent at 1000 cycles, and 49 per cent at 5000 cycles. If a caesium 
cell is used, the ratios will be 35 per cent at 200 cycles, 25 per cent at 
1000 cycles, and 17 per cent at 5000 cycles. 

Among the various sizes of lamps, the per cent modulation ratios 
show a decrease as the lamp size increases. The tabulation shows 
that a 100-w concentrated-arc lamp has less than one-half the per 
cent modulation ratio of a 2-w lamp. The 100-w lamp has about 


MM l.'o I 

FIG. 4. Frequency characteristic for 2-w concentrated-arc lamp 
taken with an antimony phototube. 

250 times the light output of a 2-w lamp; thus, even with its lower 
modulation ratio, the modulated light output of the 100-w lamp will 
be many times that of the 2-w. 

Table 1 also shows the effect of a change in the gas used to fill the 
lamp. The first four lamps listed are argon-filled, while the last is 
filled with krypton gas. By comparing it to the iOO-w argon-filled 
lamp, it can be seen that there is a considerable advantage in the 
krypton filling; the average gain in modulation ratio being 56 per 
cent for the antimony cell, and 21 per cent for the caesium cell. 
Other gases have been tried in the lamps, but these two are the most 

The complete frequency characteristic for a system consisting of a 
2-w argon-filled lamp and a caesium-type photoelectric cell js given 
in Fig 3 This shows the effect on the per cent light modulation of 



different modulating frequencies and different percent current 
modulation. For this particular combination, the maximum per cent 
light modulation shown is slightly less than 50 per cent. A linear re- 
lationship between modulated light output and modulating current is 
indicated by the uniformity of the spacing of the curves for the 
various percentages of current modulation. 

Fig. 4 shows the same characteristic for a 2-w lamp when com- 
bined with an RCA 931 A antimony- type photocell. These curves 
also show a linear light-current relationship with an increase in the 
per cent light modulation, whose maximum now exceeds 80 per cent. 

FIG. 5. Frequency characteristic of 2-w concentrated-arc lamps 
as seen by an antimony phototube through a CG587 filter. 

If the spectral region used is restricted further by the addition of a 
Corning No. 587 ultraviolet-passing glass filter so as to employ radia- 
tion which peaks around 3750 A, which might be suitable for photo- 
graphic film, a characteristic such as shown in Fig. 5, will be obtained. 
The use of this filter raises the modulation ratio by amounts ranging 
from iO per cent at low audio frequencies to 35 per cent at 10 kc. 
As a result, the 100 per cent current modulation curve of this com- 
bination shows a modulated light output which is flat to within less 
than 5 db from 100 cycles to 10 kc. 

Some gain in the depth of modulation and flatness of the light- 
frequency characteristic shown in Fig. 4 can be obtained by using a 
krypton-filled 2-w concentrated-arc lamp with the RCA type 931 A 



photocell as is shown in Fig. 6. Further gains result from the addi- 
tion of the ultraviolet glass filter to produce the curves of Fig. 7. 
These curves show a maximum light modulation of 93 per cent and a 
drop with frequency of only 2.3 db between 100 cycles and 10 kc. 
The total amount of modulated radiation emitted by concentrated - 
arc lamps can be more than doubled by increasing the gas pressure of 
argon or krypton from one to ten atmospheres as is shown by the 
curve of Fig. 8. Because of the possible danger of explosion, such 
lamps have not been made commercially. 

FIG. 6. Frequency characteristic for 2-w krypton-filled concen- 
trated-arc lamp as seen by an antimony phototube. 

The dynamic relationship between lamp current and lamp light is 
not absolutely linear. At the peak of a cycle of modulation, the 
lamp may be driven to give high light output with good fidelity. On 
the opposite half of the cycle, as the light output approaches zero, the 
response becomes nonlinear. This results in a flattening of the nega- 
tive peaks, which analysis shows to consist largely of second-harmonic 
distortion. For this reason the percentage of second-harmonic fre- 
quency in the modulated light wave is used as a measure of the dis- 
tortion of the lamps. 

A typical distortion characteristic for a 2-w argon -filled concen- 
trated-arc lamp taken with an antimony type of phototube is given in 
Fig. 9. 



Table 2 gives the percentage of second-harmonic distortion of the 
modulated light output of the several sizes of lamps taken at 75 per 
cent current modulation and at various frequencies. Percentage of 
distortion tends to rise with an increase in the percentage of current 
modulation, the lamp wattage, and the frequency. 

The random fluctuations in the light output of the lamps result in 
background noise in the systems in which they are used. When the 
2-w argon-filled lamp is used with an RCA 931 A photocell and Corn- 
ing No. 587 ultraviolet filter, the noise level- is more than 50 db below 

FIG. 7. Frequency characteristic for 2-w krypton-filled concen- 
trated-arc lamp taken with an antimony phototube through a 
CG587 filter. 

the maximum output of the lamp when it is 100 per cent current 
modulated. The majority of this noise seems to occur in the very 
low audio and subaudio frequency range and, in radio frequencies, 
between 100 kc and one megacycle. 



Per Cent Second-Harmonic Distortion at 75 Per Cent Current Modulation 







Antimony Cell (Freq.) 

Caesium Cell (Freq.) 

























April 1947 



Over a period of time, the lamps show small changes in modulated 
light output, as shown by the trace of Fig. 10. The amplitude of these 
changes in a good lamp is usually of the order of 2 db or less. The 
relative amplitude of these changes can be reduced if the lamps are 
operated at slightly higher than normal currents. This will tend to 
reduce the average life expectancy of the lamps, which for the 2-w 
lamp, operating on unmodulated direct current, is 175 hrs. When 
the lamp current is modulated, the life of the lamp may also be re- 
duced. This is probably because of loss of zirconium vapor from 
the cathode-glow region of the arc during the extreme excursions 
of the modulation cycle, particularly if the polarity actually reverses. 



100 v 












60 5 





, "" 





URE - 




NCH 2 






FIG. 8. 

Relative modulated-light output of concentrated-arc lamps 
at various gas-filling pressures. 

The intensity of the modulated component of the radiation is not 
constant over the face of the cathode spot. Fig. 11 shows the rela- 
tive values of modulated light intensity at different frequencies and at 
different positions in the cathode spot of a 100-w argon-filled lamp as 
measured with a caesium-type photocell. This diagram shows that 
the highest modulation intensities are found at the center of the spot. 

If the current through a lamp is increased slowly, the diameter of 
the cathode spot will also increase, with some slight time lag, so that 
the unit brightness of the surface tends to remain almost constant. 
If the current is varied at a frequency of a few cycles per second or 
higher, the spot diameter remains constant, and the variations in 
current produce an almost linear change in the unit brightness of the 



cathode spot. The fact that the dynamic relationship between the 
modulating current and the light output is linear, at various audio 
frequencies, is shown by the oscillograms of Fig. 12. These traces 
also show that there is a phase lag between the current and light, 

FIG. 9. Distortion characteristics of a 2-w concentrated-arc lamp 
taken with antimony phototube. 

FIG. 10. Slow changes in modulated light output of a 2-w concentrated-arc 


which increases with frequency. In the 2-w lamp, this lag rises to 

In their static characteristic, concentrated-arc lamps, like most 
arcs, show a negative volt-ampere curve. Thus, as the current is 
increased, the voltage across the lamp drops, giving the electrical 



effect of a negative resistance. For stable operation, positive resist- 
ance must be added to the circuit in an amount sufficient to match 
the negative resistance of the arc and leave a positive surplus. 

Fig. 13 shows oscillograms of the volt-ampere characteristic of a 
2-w lamp at various audio frequencies. At 10 cycles, the negative 
slope is quite similar to that of the static characteristic; but, as the 
frequency increases, the pattern opens up, showing a negative char- 
acteristic over only a part of the cycle. 

5,000 - 

10,000 - 

FIG. 11. Relative modulated brightness at 
various frequencies and at different parts of the 
light-source spot of a 100-w concentrated-arc 

Impedance and phase characteristics of 2-w lamps are shown by the 
curves of Fig. 14. When operated at rated current and 50 per cent 
current modulation, the lamp acts as an inductive load with an aver- 
age impedance, over the audio-frequency range, of about 200 ohms. 
As the frequency increases, this impedance Z at first decreases, reaches 
a minimum of 150 ohms at 1200 cycles, and then increases to 270 
ohms at 10 kc. The resistive component R of this impedance has a 
value of minus 260 ohms at 100 cycles, reaches zero at 2600 cycles, 
and rises to 200 ohms at 10 kc. The voltage-current phase-angle 
curve B EI shows that the current lags the voltage, the lag decreasing 
as the frequency increases. The light always lags the current, the 
amount increasing with frequency, as shown by the current-light 
phase-angle curve IL . 



The impedance and phase characteristics of the larger wattage 
lamps show similar trends. Fig. 15 shows that the impedance of the 
10-w lamp is 7 ohms at 1000 cycles, and that its resistive component 
becomes positive at 900 cycles. 

The 25-w lamp of Fig. 16 shows an impedance of 5 ohms at 1000 
cycles, and its resistance is positive at frequencies above 200 cycles. 

Fig. 17 shows the same trends for the 100-w lamp. Here the 1000- 
cycle impedance is 1.5 ohms and its resistance becomes positive at a 
frequency less than 100 cycles. 

FlG. 12. Oscillograms of the dy- 
namic light-current characteristic of a 
2-w concentrated -arc lamp at various 

FIG. 13. Oscillograms of the dy- 
namic volt-ampere characteristics of a 
2-w concentrated-arc lamp at various 

Modulating circuits for concentrated-arc lamps are of two general 
types. The first, shown in Fig. 18, is applicable to 2-w lamps only. 
The impedance of this lamp is high enough so that it can be connected 
directly into the plate circuit of a vacuum tube, such as a 6L6, the 
modulating voltage being applied to the grid. Only 0.055 amp of 
direct current is required to maintain the arc, and this can be sup- 
plied by the normal plate current of the modulator vacuum tube. 

In this circuit, the lamp is started automatically by a small spark 
coil, which is controlled by a relay in series with the lamp. In 

April 1947 



practice, a pentode connection for the modulator tube would be pre- 
ferred because of the stabilizing effect of the higher plate impedance 


rr. I00 i i i i j 

FIG. 14. Impedance and phase characteristics of 2-w concentrated- 
arc lamps. 

FIG. 15. Impedance and phase characteristics of 10-w concentrated- 
arc lamps. 

and its more nearly constant current characteristic. There are 
also advantages in the use of negative current feedback. 

Fig. 19 shows a type of modulator circuit which can be employed 
with all sizes of concentrated-arc lamps. Here, the lamp is coupled 



to the modulator tube through a suitable impedance matching trans- 
former, and the direct current for the arc is drawn from a separate 
supply. Manual starting is used in this circuit. The high voltage 


I0 \ 
















UJ 1 

- S-l 




' s 


8 i 





S ' 











** * 





1 < 











r ** 












30 ! ' | 






10,000 ^| 

FIG. 16. Impedance and phase characteristics of 25-w concen- 
trated-arc lamps. 

I .'000 I I I I I 

FIG. 17. Impedance and phase characteristics of 100-w concen- 
trated-arc lamps. 

necessary to start the arc is obtained from an inductive surge produced 
when a vacuum-type shorting switch is opened in the highly induc- 
tive direct-current supply circuit. 

April 1947 



In the design of such modulators, consideration must be given to 
the unusual impedance characteristics of the lamps. For example, 
the 2-w lamp has a negative resistance at frequencies lower than 2600 

FIG. 18. Direct-coupled modulator circuit for 2-w concentrated- 
arc lamps. 

FIG. 19. 

Transformer-coupled modulator circuit for concentrated- 
arc lamps. 

cycles. If this lamp is put into a circuit whose natural resonance is 
less than 2600 cycles, and if the positive resistance of the circuit is 
less than the negative resistance of the lamp, the circuit will oscillate. 
Thus, resistance must be added to some circuits to secure stability. 

340 W. D. BUCKINGHAM AND C. R. DEIBERT Vol 48, No. 4 

The actual power required to modulate the lamps, with the nec- 
essary circuit and stabilizing resistance, varies from about 2 w for a 
2-w lamp to 50 w for a 100-w lamp. Modulating power require- 
ments, for a given percentage of current modulation, rise -with the 
increase of modulating frequency for all sizes of lamps. 

A concentrated-arc lamp thus furnishes a source of modulated 
radiation which has unique and useful characteristics. The 2-w 
lamp, in particular, is adapted to applications requiring a source of 
high brightness, high percentage of light modulation, low background 
noise, and high fidelity. 


1 BUCKINGHAM, W. D., AND DEJBERT, C. R.: "The Concentrated-Arc Lamp," 
/. Opt. Soc. Arner., 36, 5 (May 1946), p. 245. 

2 BUCKINGHAM, W. D., AND DEIBERT, C, R.: "Characteristics and Applica- 
tions of Concentrated-Arc Lamps," /. Soc. Mot. Pict. Eng., 47, 5 (Nov. 1946), 
p. 376. 


MR. R. S. LEONARD: What is the output of the 100-w lamp in lumens? 

MR. BUCKINGHAM: On a candlepower basis, the 100-w lamp is quite similar 
to the 100-w tungsten filament lamp, giving about one candlepower per watt. 
Since the lamps have a cosine spatial distribution rather than spherical, when 
you convert from candlepower to lumens, you can multiply only by pi instead 
of four pi, so the lumen output of a 100-w lamp is pi times 100, or about 300 
lumens. That is the reason we do not recommend these lamps for applications 
where total quantity or lumen output is important. Their use is indicated where 
the high brightness of the source is of major importance. The brightness is 
several times that of a tungsten filament and in many places that is very useful. 
Also, the source is so extremely small that in optical systems it has the advantage 
of forming the stop of the system in many applications to give unusual results. 
But the lumen output is only one-fourth of that of the corresponding tungsten 
lamp with equal efficiency. 

MR. LEONARD: What would be the expected life at 3000-cycle operation of 
the 100-w size continuous? 

MR. BUCKINGHAM: We do not know. We have had some experience that 
indicates that the life is less under conditions of modulation than it is when 
operated with direct current, but now and then we have a lamp that comes along 
and lasts and lasts and lasts, under conditions of modulation, which I guess only 
proves that our lamps are not all exactly alike. For example, we have a 10-w 
lamp operating in New York City now which has been going steadily for over six 
months. I do not know the number of hours that would figure out, but since we 
expect a life of about 800 hr for the 10-w lamp, something is wrong there. So I 
do not know what length of life you would get in a 100-w lamp. 

MR. LEONARD: Would you estimate in terms of hours just roughly? 


MR. BUCKINGHAM: I would guess you would get somewhere near the normal 
length of life, which is 1000 hr. We think if you over-modulate the lamp so 
as to reverse the polarity, you may carry away enough of the active material to 
shorten the life very greatly. 

DR. J. G. FRAYNE: What is the signal-to-noise ratio, approximately? 

MR. BUCKINGHAM: It was not on the curve, but I gave it as being better 
than 50 db below the maximum output of the lamps. We do not know the exact 
figure because when we got 50 db below, we ran into 60-cycle hum which we 
were picking up because of an inadequate filter in the power supply. 

DR. FRAYNE: Have you made any recordings on film? 

MR. BUCKINGHAM: We have not. Being a communication company we do 
not have those facilities. That was one of the reasons for coming out here. We 
are hoping that somebody with those facilities will make the test and see what 
.actually turns up. 

MR. L. G. DUNN: Can you tell us the progress being made with high-wattage 

MR. BUCKINGHAM: There has been a great deal of interest in the higher 
wattage lamps, and we have had them up to about 1500 watts in operation in 
the laboratory. The 1500-w lamp, for example, has a source spot about 3 /s in. 
or a little less in diameter, giving about 4000 cp. This means that it has a. unit 
brightness which figures out about 70 candles per sq mm. That is a large enough 
spot size so that it could be used in a 35-mm projector with an ordinary con- 
densing system. We have been working hard on this particular phase of the lamp 
development, because there is so much interest in it, and expect shortly after 
the first of the year to have something that we can show people. The lamps so 
far have been of a highly experimental nature, but very, very promising in their 

MR. DUNN: What specific applications have been made? 

MR. BUCKINGHAM: The applications that have been made so far have been, 
of course, with the smaller lamps, which are now available, the 2- to 100-w sizes. 
The major applications have been perhaps in the field of photography and micro- 
scopy. In a photographic enlarger the use of the point source lamp in a condenser 
system acts as a stop of the lens system so that the pictures you get are extremely 
sharp in comparison to those you would get on the same system using a larger 
source lamp. 

MR. P. A. WILLIAMS: Mention was made of the appreciable radiation of these 
lamps in the ultraviolet and infrared regions and it would seem that the latter 
would be a rather important factor in the heat radiation and necessary cooling 
equipment. It would be interesting to learn whether or not it has been found 
necessary to provide forced air or other means of cooling when these lamps are 
used in enclosures. 

It is also suggested that some information be provided regarding the effects 
of operating temperature on the light output/ Several attempts have been made 
in the past to use gaseous discharge tubes for photographic printing but the 
variability of light output with temperature has made the practical use of such 
sources rather difficult. 

MR. BUCKINGHAM: The spectrum of the concentrated-arc lamp differs from 
that of the tungsten-filament lamp only in that it shows a few sharp peaks of 


line radiation which originate in the gas discharge and also in that the concentrated 7 
arc lamp is several times as bright as the tungsten-filament lamp. 

There is no greater proportion of ultraviolet or infrared in the output of 
a concentrated-arc lamp considering its increased brightness in the visible. It 
has the same advantages in these spectral regions as it has in the visible, those 
of high brightness or concentration of energy and small-source size. 

From a practical standpoint, 100 w of electrical energy put into a concentrated- 
arc lamp will produce no more heat than 100 w put into a tungsten-filament lamp. 
However, because of the high brightness of concentrated-arc lamps, it is possible 
in some applications to substitute a 100-w concentrated-arc lamp for a 500-w 
tungsten-filament lamp without decreasing the useful light output of the equip- 
ment. In this case, there will be only one-fifth as much heat given off by the 
concentrated-arc lamp as by the tungsten lamp. 

The second question has to do with the effect on lamp operation of the room or 
operating temperature. We have been unable to detect any difference in the lamp 
operation or light output as the external temperature is varied over a range of 
several hundred degrees. The lamps are not critical in this respect. 



Summary. This paper describes a method of automatically silencing the 
splices on work prints used for rerecording. Holes are punched in the picture area 
of the sound track by means of a convenient foot-operated punch, at a fixed distance 
from each splice. These holes then serve to operate a switch in the rerecording head so 
that the sound output is momentarily cut off while the splice is passing the scanning 

The need for a satisfactory method of silencing or "blooping out" 
the noise caused by splices in sound track has been recognized since 
the inception of sound pictures. This need is especially felt when 
preparing the sound tracks for final rerecording, at which time origi- 
nal dialogue, narration, music, and sound effects tracks are blended 
together to make a single continuous negative, free from any noises 
caused by splices on the original tracks. Various methods are in use, 
some operating on the print, and others on the negative. 

Common methods for treating the positive consist of painting over 
the splice with various types of ink, spraying the splice with an air 
gun containing the ink, while covering the area of the splice with a 
triangular shaped mask, or covering the splice with a special adhesive 
tape cut in triangular form. 

When operating on the negative, the principal method is to punch 
a triangular hole over the splice which prints through opaque on the 
positive. The second method is to produce a flash exposure in the 
printing machine at each negative splice. 

All of the above methods are very effective when properly ac- 
complished, but all require extreme care in handling the film so as not 
to introduce extraneous noise caused by dirt, and all are time-con- 

* Presented Oct. 24, 1946, at the SMPE Convention in Hollywood. 
** Chief, Sound Branch, Studio Division, Signal Corps Photographic Center, 
Long Island City, N. Y. 




Vol 48, No. 4 

In most of the pictures produced at SCPC, the negative is not cut, 
and all cutting and rerecording operations are carried out on the 
work print. In the case of "lip-sync" type of picture, where foreign 
dialogue is recorded to match the lip movements of a picture which 
was originally photographed with English dialogue, it is not uncom- 
mon to have as many as 250 splices in a single reel. It can readily 
be appreciated, therefore, that the blooping operation assumes major 
importance when preparing a print for the rerecording process. 

FIG. 1. Switch and actuating mechanism installed on rerecording 


The machine about to be described was developed for the purpose 
of eliminating, as far as possible, the tedious and time-consuming 
operations of blooping sound film, and at the same time resulting in 
sound tracks which are quieter as a result of avoiding the handling 
necessary with hand blooping. The operating principle adopted is to 
shut off the sound automatically whenever a splice passes the scan- 
ning beam. Three methods of accomplishing this effect were tried 
before the third method was finally adopted. 

The first method consisted of introducing a variable-gain amplifier 
into the output of the rerecorder. This permitted accurate control 

April 1947 



of the rate of decay and restoration of the signal. It proved very 
effective in silencing an oscillator tone with complete absence of 
clicks, but peculiarly it developed that this method caused a notice- 
able thump in the background noise of the film. 

The second method attempted automatically to block the exciter 
light with a properly shaped mask to produce the same wave form as 
is obtained with a good ink or tape bloop. This method showed 
great promise but involved mechanical difficulties, and was abandoned 
when it was found that the third method pr.oved to be the simplest as 
well as the most effective. 

FIG. 2. Film-punghing table. 

This third method consisted simply of switching off the sound 
from the rerecorder momentarily with an automatically operated 
switch, whenever a splice went through. The switch is located in the 
rerecording head itself and is operated as described below. Elec- 
trically, the switch is connected in the output of the preamplifier, just 
ahead of the input to the mixer. This ensures maximum signal-to- 
noise ratio as regards any electrical noise the switch might introduce. 

The principal problem remaining was the method of operating the 
switch. Consideration was first given to the possibility of having 
the thickness of the splice itself operate the switch, but it was feared 
that this might prove too delicate for practical use. It would also 



Vol 48, Xo. 

require the use of time-delay circuits, or else undergo the possibility 
of introducing flutter in the film motion through the use of contacting 
mechanisms close to the scanning beam. 

It was, therefore, decided to punch a hole in the film at a fixed dis- 
tance from each splice and use this hole to provide positive operation 
of a sensitive switch. This method also provided the advantage of 
permitting adjustment of the duration of cut-off simply by varying 
the length of the hole. Where two or more splices occur within the 
space of a few inches, with no intervening modulation, which is often 
necessary to improve synchronization, it is possible to blank the en- 
tire duration simply by overlapping two or three punch holes. 

FIG. 3. Film in position for punching. 

Fig. 1 shows the installation of the actuating mechanism in a re- 
recorder. A light coil spring is placed over, the plunger arm to pro- 
vide positive return pressure, rather than rely on the relatively feeble 
spring return in the switch itself. The actuating roller is swung up 
out of the way when threading the machine. It can be left in the 
"up" position whenever it is desired to run prints which do not re- 
quire machine blooping, or have been blooped by conventional 

Fig. 2 shows the film punch table used by the operator in prepar- 
ing the sound track. The punch itself is foot operated, leaving both 
hands free to handle the film. 

Fig. 3 shows a close-up of the film guide-plate. The register pins 
serve to positively determine the position of the splice so that the 


distance from splice to hole is accurately fixed. This distance and 
the length of the hole were set so that the switch operates approx- 
imately 0.025 sec before the splice enters the scanning beam, and 
remains closed for a total duration of approximately 0.050 sec. These 
dimensions have proved adequate for the most closely cut splices, 
while at the same time allowing a tolerance of at least one sprocket 
hole either way in threading the rerecorder. 

The film punching machine has been laid out so that the sound 
track remains outside the punch with the emulsion side up, thus min- 
imizing the possibility of scratching the film. 

It is estimated that this machine reduces the time necessary for 
blooping a reel to a negligible fraction of the time normally required 
to do a good hand-blooping job. Where formerly it was necessary 
to spend a day or more in preparing and then making corrections in a 
reel, it is now done in anywhere from ten minutes to one hour. Fur- 
thermore, it can be successfully operated by semiskilled personnel 
with practically no special training. The most important saving 
of all is, of course, the avoidance of long delays during rerecording 
sessions while noisy bloops are located and painted out. 

The machine has also proved useful in blooping out noises result- 
ing from causes other than splices such as accidental scratches and 
dirt marks on the film, and pin holes in the emulsion. 

Should a hole be accidentally punched in the wrong location, it can 
be corrected simply by applying a piece of scotch tape over the hole. 

Credit for the design and construction of the punch and switch 
actuating mechanism is due the personnel of Sound and Machine 
Shop Branches of Studio Division. 

[Ed. Note. A sound film was projected demonstrating the effective- 
ness of the blooping devive. The film consisted of a typical narra- 
tion track, rerecorded first without and then with the antiblooper in 
operation. In order to accentuate the operation, numerous extra 
splices, closely spaced, were made in the original track. Each splice 
was scraped of emulsion to make it unusually loud. The complete 
silencing of the splices in the second rerecording was evident.] 



Summary. This paper describes three innovations in studio stage construction: 
{1} Vertical-Lift Stage Separation Doors. These doors eliminate the hinged type 
formerly used, which required so much valuable stage space. Ease of operation and 
good sound insulation have been obtained between adjacent stages. (2} A Movable 
50-Foot Transparency Screen. A screen has been suspended from a monorail sys- 
tem for storage outside the stage. It can be readily rolled into position in the space 
normally occupied by the vertical lift doors to permit large screen transparency shots to 
be made between two connecting stages. (3} A Vertical-Lift Disappearing Bulk- 
head for a Stage Water Tank. A hydraulically lifted bulkhead has been designed 
which permits a large sound stage to be quickly converted into a 7 -ft deep tank. 

Vertical Lift Stage Separation Doors. With the ever-increasing 
demand for larger and improved motion picture stages, the archi- 
tectural, engineering, and allied professions have made great strides 
and improvements in keeping abreast of the constantly changing 
techniques and new demands for improved facilities. 

Ingress and egress to motion picture stages has, from the beginning 
of stage operation, presented an important problem. The conven- 
tional hinged, sliding, and vertical raising doors have filled the needs 
where this type installation served the purpose best. However, in 
many instances sacrifices were made either in size of opening or other 
restrictions imposed by utilities or building limitations. 

The ever-increasing scope to accommodate extensive motion picture 
sets and provide for unusual effects has created a demand for larger 
stages, which in themselves may prove an. extravagance economically 
where an entire stage may be required to accommodate a compara- 
tively small motion picture set. 

With this in mind, the Engineering Department of Paramount 
Pictures, Inc. undertook the problem of devising a means of dividing 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** Chief Engineer, Paramount Pictures, Inc., Hollywood. 



a large stage area under one roof into smaller areas. Obviously, such 
an arrangement provides a greater flexibility in the use of the area as 
the occasion demands. Accordingly, plans were prepared and an 
installation made between Stages 1214 and Stage 15, the former 
containing 17,630 sq ft, the latter 17,668. The opening separating the 
two stages is 60 ft wide and 38 ft high. The vertical raising sections 
consist of a pair of leaves on each side, divided in the center. The 
sections are raised into an overhead well so that when the maximum 
height is reached, the plane of the bottom chord line of the stage 
trusses in unobstructed. The total weight of the vertical sections is 
approximately 40,000 Ib. The leaves are constructed of structural 
steel frames into which is incorporated the insulation and finishing 
materials for the desired attenuation. The opening is provided with 
sealing features at the top, at the center horizontal joint of the leaves, 
and at the floor, and has an automatic self-sealing device in the 
jambs. A structural separation is provided between the doors with 
necessary isolation at jambs, head, and floor for greater attenuation. 

The structure supporting the overhead well consists of an inde- 
pendent superstructure housing, supported by two frame towers at 
the jamb sides. The towers are designed to accommodate the counter- 
balance space and arbors. The overhead truss structure, in addition 
to supporting the weight of the vertical sections, also accommodates 
the hoisting mechanism. 

Each vertical raising section is electrically operated with a 5-hp, 
2-speed, constant torque, 22-v, 3-phase, 60-cycle motor in conjunc- 
tion with the mechanical brake, upper and lower limit switches, slow- 
down switches and a reversing controller providing automatic ac- 
celeration, antiplugging on de-acceleration to final lowered position 
and locked with limit switches. 

After the installation was completed, a sound test was made by 
placing a loud speaker and microphone at selected positions within 
the large area closed by the door. Warble tone at selected frequen- 
cies was applied to a loudspeaker (Lansing Iconic used by the studio 
for playback monitoring) which was shifted to selected positions 
within the opening closed by the door and with the face of the loud- 
speaker approximately two feet from the surface of the door. A 
6 18 A microphone on the other side of the door and opposite the cor- 
responding loudspeaker position picked up the sound level from the 
loudspeaker for measurement on an RA-142 Sound Level Meter. 
The difference in levels between the open door and that obtained 

350 A. C. ZOULIS Vol 48, No. 4 

with the door closed represents the attenuation caused by the door. 
This method of direct comparison eliminates differences resulting 
from response of loudspeaker, microphone, etc. 

In comparison with the attenuation of the wall construction used 
in the stage where the installation was made, the measurement indi- 
cates that the door, when fully closed, provides a relatively good insu- 
lation against the transmission of sound for the frequency range 
checked. This was indicated from the measurements taken which 
were from frequencies of 150 to 500 cps. Under these conditions, the 
measurements tend to concentrate between the levels of 38 to 45 db 
and 57 to 60 db, respectively. The measurements of the frequencies 
above 500 cps tend to concentrate within the levels of 63 to 66 db. 

Movable 50-ft Transparency Screen. The advantage of using 
large transparency screens for background projection purposes has 
increased the scope of this activity to an important function within 
the motion picture industry. Transparency screen techniques have 
made possible the incorporation of animated interiors and ex- 
teriors within the confines of a motion picture sound stage, resulting 
in drastically reduced production costs. These improvements, to a 
large extent, have replaced former procedures required by locations 
for the backgrounds desired. 

The problem of handling and storing large screens is in direct pro- 
portion to their size. Since it is not practical to remove acetate 
screens from their rigid frames and roll them into a compact unit for 
storage, numerous methods have been employed. 

A practical method for the storage of a large 50-ft screen is em- 
ployed at Paramount Pictures, Inc. The installation consists of a 
large storage enclosure approximately 8 X 62 ft on the exterior and 
adjoining the stage equipped with monorail for handling the screen. 
In designing the screen storage housing, particular attention was 
given to the construction details to exclude dust particles and to pro- 
vide for eventual screen size expansion. Within the storage area 
the screen, attached to carriers, is suspended from a monorail which 
connects to the system within the adjoining stage. When occasion 
demands use of the screen on the stage, the screen is moved through a 
door especially constructed to accommodate full height of the screen 
and then transferred to a crane beam suspended from the monorail 
system attached to the overhead trusses within the stage proper. 
The screen is then ready to be moved longitudinally within the stage 
to the required foreground position. Chain hoists at each end of the 


crane beam which support the screen permit vertical adjustment as 
required for the height above stage floor. 

In conjunction with the crane beam for screen movement, a light 
bridge to accommodate lighting equipment is suspended from an 
independent monorail system above the top of the screen proper. 
This permits the light bridge to be placed at the most advantageous 
location for properly lighting the screen foreground and for shadow 
elimination. Chain hoists at each end of the light bridge permit 
vertical adjustment to coincide with the transparency screen crane 
beam. Canvas roller curtains for each side of screen frame are pro- 
vided to cover and protect screen while not in use or when being 
moved about the stage or into the storage area. 

Vertical Lift Disappearing Bulkhead for a Stage Water Tank. 
The use of concrete tanks within a motion picture stage for water 
effects when required for production has long been established as a 
decided advantage over exterior locations without benefit of sound- 
proofing, acoustical control, or other standard facilities. 

The problem of providing a vertical lift bulkhead to permit direct 
access to the stage floor from the exterior without grade interruptions 
and also to make possible the use of a continuous floor level with ad- 
joining stage without temporary bulkheads, was recently studied by 
the Engineer ng Department of Paramount Pictures, Inc. The 
walls of an existing concrete tank within the stage are 8 ft high. Op- 
posite the opening to an adjoining stage, a vertical lift steel bulkhead 
60 ft long and 7 ft high has been installed. The installation consists 
of a subsurface elongated well to permit vertical movement of the 
bulkhead. When lowered, the top cover plate is flush with the sur- 
rounding tank floor and adjacent stage area. 

The operation of the bulkhead, which weighs approximately 20,000 
pounds, is through a sheave system and counterbalance with suf- 
ficient weight differential between counterbalance and weight of 
bulkhead for sufficient ease of handling. The counterbalance is 
located at the center of the bulkhead compartment and is raised or 
lowered with a 5-ton chain block. The bulkhead is adjustable in 
vertical height from zero at floor level to 7 ft above floor. Within 
these limits the bulkhead may be locked into position with a manually 
operated 50 : 1 reduction worm and bevel pinion gear on a continuous 
shaft, to which are attached eccentric cams, the rotation of which 
actuates toggles secured to the sealing mechanism to make the bulk 
head water-tight at sides and bottom. 

352 A. C. ZOULIS 

Provisions have been made in the bulkhead cover plate to permit 
additional construction to accommodate transparent spillway or to- 
raise the over-all height to coincide with the 8-ft concrete tank side 



Summary. A method is described for electronically modulating small incan- 
descent light sources to stimulate the effect of gas flame flicker and light emanating 
from a fireplace. The effect produced is more natural than can be obtained with 
dimmer and flasher methods and is entirely automatic. 

When photographing motion picture sets using gas light brackets, 
it has been common practice to conceal a 50- or 100-w projection 
lamp back of each shade to reinforce the light from the gas flame, as 
the flame itself does not produce enough light for satisfactory photo- 
graphic results. These lamps are usually controlled by means of a 
flasher and dimmer combination to simulate the flicker of the gas 
flame on the wall, as shown in Fig. 1. The results obtained are more 
or less mechanical and require the constant attention of an operator. 

Some time ago we received a request from the Decorative Lighting 
Department to develop an automatic control for these lights that 
would make them synchronize exactly with the flicker of the gas 
flame. If the gas light is turned up, or turned down or out, the 
reinforcing light must follow the action faithfully as well as producing 
the flicker, and it must do this without any manual operations. 

This was accomplished with a simple electronic control in the fol- 
lowing manner: The light from the gas flame in the bracket was 
picked up with a photocell attached to the back of the bracket shade 
and concealed from the camera (Fig. 2) . The photocell was connected 
in a phase-shift circuit which controlled the grid of a thyratron tube. 
The lamps that produce the reinforcing light were connected in the 
anode circuit of the tube and the light produced could be made di- 
rectly proportional to the amount of light picked up by the photo- 
cell. The cell was enclosed in a metal shield with a tubular window so 
arranged that it could pick up the light from the tip of the gas flame 
and not be affected by the normal set lighting. 

* Presented Oct. 21, 1940, at the SMPE Convention in Hollywood. 
** Warner Bros. Pictures Inc., Burbank, Calif. 




Vol 48, No. 4 

The thyratron unit controls the current through the lamp. The 
light reproduced on the wall was a very faithful reproduction of the 
gas flame flicker and the lag in response could not be detected. The 
circuit, with the omission of protective devices, is shown in Fig. 3. 


50 OR 100 WATT 


FIG. 1. Method ordinarily used for concealing a small 
projection lamp back of a gas bracket to reinforce the 
light produced by the gas flame. 

115 V 




50 OR 100 WATT 

FIG. 2. 

An electronic circuit is added to modulate the projection 
lamp to simulate gas flame flicker. 

The thyratron employed was an FG-105, which is a shield grid 
type and is rated at 6.4 average amp, and it will take care of the re- 
quirements of the average set to be photographed in black and white. 
Tz is the anode transformer which must be capable of carrying the 



entire lamp load. T\ is the grid transformer which handles very 
little power. Pi is a potentiometer connected across the secondary 
of the grid transformer and serves as the sensitivity control. 

The section AB of this potentiometer, the secondary of the anode 
transformer, the capacitor C, and the photocell, form a resistance- 
capacitance phase shift bridge in which the photocell serves as the 
resistive element. This bridge controls the phase angle of the grid 
voltage relative to the anode voltage. The phase angle of the grid 
voltage determines the amount of current that flows through the 
thyratron and the load. 

FIG. 3. Half -wave electronic circuit for modu- 
lating incandescent lights. 

The sensitivity control is adjusted so that when no light strikes the 
cell the grid voltage is about 180 deg out of phase with the anode 
voltage and the tube does not conduct. Small increments of light 
on the photocell decrease the angle by which the grid voltage is dis- 
placed from the anode voltage, and the tube starts to conduct. When 
there is sufficient light on the cell, the grid and anode voltage are 
practically in phase and the thyratron conducts maximum. 

The photocell used was a 922, which is a vacuum cartridge type. 
This particular cell was selected because it could be mounted in a 
small housing. 

The capacitor C is in the neighborhood of 0.0003/xf - The grid cir- 
cuit is a high impedance circuit and should be properly shielded. Ri 
is the grid resistor used for the protection of the thyratron grid. 

356 H. NYE Vol 48, No. 4 

The sensitivity control is the only adjustment in the circuit. With 
this control the lights can be phased full on, off, or the photocell can 
be given any desired amount of control, i. e., the flicker can be made 
violent or barely perceptible. The rate of flicker, of course, depends 
on the flicker of the gas flame. All the operator has to do is to adjust 
the sensitivity control until the flicker looks natural to the eye. Any 
operator can run the equipment with a few minutes instruction. 

The characteristics of mercury thyratrons vary slightly until they 
reach their operating temperature and some adjustment of the sensi- 
tivity control may be necessary for the first half hour, but after the 

FIG. 4. Equipment used for electronic flicker effect. 

tube has heated sufficiently, no further attention is required from the 

A five-minute time delay relay is required to delay the application 
of the anode voltage until the cathode has reached its operating 
temperature. This relay, switches, fuses, and pilot lights are omitted 
from Fig. 3. 

A photograph of the original equipment as used is shown in Fig. 4. 

A is the photocell in a metal housing set so it will pick up 
the flickering light from the gas flame. No optical system is used. 
Since one photocell terminal is common with one of the power lines to 
the lamp, it is necessary only to run one lead from the photocell to the 
thyratron grid circuit. Trouble was encountered when we tried to 
cable this lead along with the power leads, even though it was shielded, 



but bare wire can be used if it is kept away from the power leads. A 
piece of No. 38 bare copper wire run from the sensitive side of the 
photocell to a pin driven through the wall serves as this lead and it is 
so fine that it will not photograph. A lead fastened to the other end 
of the pin on the back of the set connects to the grid post on top of the 
thyratron unit which is in the center of the picture. 

The pilot light B indicates that the filament is turned on. The 
pilot C lights when the time delay relay has applied the anode voltage. 
The pilot D is connected across the load and permits the operator to 
observe the flicker being produced even though he is not in a position 
to see the lights on the set. E is the sensitivity control, F is the anode 

FIG. 5. Full-wave flicker and fire effect. 

fuse compartment, G is the filament fuse, H is an external cathode 
connection which is not used in this setup, and J is a ground connec- 
tion. It is not necessary that the equipment be grounded as no in- 
terference is created with the sound recording equipment. 

The unit on the right of Fig. 4 contains the anode transformer. 
The unit shown has a varitran and voltmeter built into it, and while 
not absolutely essential, it is convenient to be able to raise the anode 
voltage somewhat above normal when the maximum light picked up 
by the photocell is insufficient to produce a 180-deg phase shift of 
grid voltage. 

In some long shots we connect as many as ten bracket lights to one 
of these electronic units. The fact that all of the lights are con- 
trolled from one flame is not obvious in a long shot. 



Vol 48, No. 4 

Small lighting units such as Dinky Inkies or Baby Juniors are also 
controlled by these units when it is desired to have the light flicker 
over some local area. 

Light sources of 250 w or less respond to the flicker modulation 
better than the larger units because the thermal inertia of large lamp 
filaments filter out much of the higher frequency component of the 
flicker. Photoflood lamps of the same wattage produce better re- 
sults than the regular projection lamps. 

FIG. 6. Laboratory setup of full- wave flicker and fire effect. 

Gas flames are usually used in fireplaces on motion picture sets, and 
here again it is necessary that the light produced be augmented with a 
flickering incandescent light source in order to produce sufficient 
light to photograph satisfactorily. The unit just described is ideal 
for controlling these lights when not more than 750 w are required. 
This wattage is ample for the ordinary fireplace to be photographed 
in black and white. When used for a fireplace effect, the photo- 
electric pickup is made from a gas pilot flame located off stage. 

When more than 750 w are required, two setups like the one just 
described may be used or a full- wave unit consisting of two thyratrons 
may be used. A full- wave circuit is shown in Fig. 5. 



This circuit operates on the same principle as the one shown in 
Fig. 3. A vacuum tube and an interstage transformer have been 
added to the circuit so that the voltages applied to the grids of the 
two thyratrons are 180 deg out of phase with each other. The anode 
transformer must have a center tapped secondary, and although 
batteries are shown in Fig. 5, a power supply was actually used. 
Fig. 6 shows a laboratory setup of this circuit. The gas burner A and 
the photocell housing B are similar to the pickup system used for a 
fireplace effect. The equipment shown at C is a bread-board setup 
of the control circuit. D is a full wave thyratron unit, E is the anode 
transformer and variac, and F is a lamp bank of photofloods which 
serves as a load. This setup has been tested for some time in the 


FIG. 7. Electronic fire effect utilizing a satu- 
rable reactor. 

laboratory and appears to operate very satisfactorily but it has not 
been built up for use on production. 

The gas burner should be in a chimney so that it can create its own 
draft and be independent of drafts that exist on the stage. The air 
holes for the burner should be properly located and be made adjust- 
able so that any amount of flicker can be produced. 

If, for any reason, it is not possible to place the photocell close to 
the gas flame, the cell may be located several feet away and the image 
of the flame can be focused on the cell with a simple optical system. 

Electronically controlled saturable reactors can be used for fire- 
place effects, but they are not so satisfactory as the circuits already 
described. The circuit for such a unit is shown in Fig. 7. The grid 
circuit of the 2050 thyratron is the same as that shown in Fig. 3. 
The saturable reactor has a capacity of 500 va and the direct-current 
winding can saturate the core with about 100 mils flowing through it. 

360 H. NYE Vol 48, No. 4 

The tube load is highly reactive and the 83 tube forms a path for the 
current because of the collapse of the direct-current field. With this 
"free-wheeling" circuit it is necessary that only one tube be grid con- 

The only advantage of this circuit is that small tubes are used and 
it is cheaper to build. The disadvantage is its slow response caused 
by the lag in the reactor. With a well-designed saturable reactor, 
not larger than 500 va capacity, it is possible to produce a fair fire- 
place effect. 

Some experiments have been conducted using ignitrons to control 
heavy loads such as might be used for large fires, but these experi- 
ments have not progressed far enough to reach arty definite conclu- 

We have been using some of these electronic fire and flicker effects 
for about a year and the results have been very satisfactory. 



.Past-President Engineering V ice-President ExecutiveVice-President 



Financial Vice-President Editorial Vice-President Convention V ice-President 

* Term expires Dec-131, 1947; ** Term^expires Dec. 31, 1948. 














* Term expires Dec. 31, 1947; ** Term expires Dec. 31, 1948. 






Governor Governor 



Atlantic Coast Section 


Midwest Section 


Pacific Coast Section 


* JAMES FRANK, JR., Chairman 
*FRANK E. CAHILL, JR., Past-Chairman 
*H. EDWARD WHITE, Sec.-Treas. 



* Term expires Dec. 31, 1947; ** Term expires Dec. 31, 1948. 



**W. C. DEVRY 

*A. SHAPIRO, Chairman 
*ROBERT E. LEWIS, Sec.-Treas. 



*G. M. BEST 


* WALLACE V. WOLFE, Chairman 
*HOLLIS W. MOYSE, Past-Chairman 
*S. P. SOLOW, Sec.-Treas. 

**F. L. EICH 


* Term expires Dec. 31, 1947; ** Term expires Dec. 31, 1948. 


(Correct to Apr. 1, 1947) 

ADMISSIONS. To pass upon all applications for membership, applications for transfer and 
to review the Student and Associate membership list periodically for possible transfers to the 
Associate and Active grades, respectively. The duties of each committee are limited to applica- 
tions and transfers originating in the geographic area covered. 

D. B. JOY, Chairman 

30 East 42d St. 
New York 17, N. Y. 




133 E. Santa Anita Ave. 
Burbank, Calif. 



BOARD OF EDITORS. To pass upon the suitability of all material submitted for publica- 
tion, or for presentation at conventions, and publish the JOURNAL. 

A. C. DOWNES, Chairman 

2181 Niagara Dr. 
Lakewood 7, Ohio 




CINEMATOGRAPHY. To make recommendations and prepare specifications for the 
operation, maintenance, and servicing of motion picture cameras, accessory equipment, studio 
and outdoor set lighting arrangements, camera technique, and the varied uses of motion picture 
negative films for general photography. 

J. W. BOYLE, Chairman 

1207 N. Mansfield Ave. 
Hollywood, Calif. 


COLOR. To make recommendations and prepare specifications for the operation, mainte- 
nance, and servicing of color motion picture processes, accessory equipment, studio lighting 
selection of studio set colors, color cameras, color motion picture films, and general color photog- 

J. A. BALL, Chairman 

12720 Highwood St. 
Los Angeles 24, Calif. 





* Advisory Member. 



CONVENTION. To assist the Convention Vice-President in the responsibilities pertaining 
to arrangements and details of the Society's technical conventions. 

W. C. KUNZMANN, Chairman 

Box 6087 
Cleveland 1, Ohio 



EXCHANGE PRACTICE. To make recommendations and prepare specifications on the 
engineering or technical methods and equipment that contribute to efficiency in handling and 
storage of motion picture prints, so far as can be obtained by proper design, construction, and 
operation of film handling equipment, air-conditioning systems, and exchange office buildings. 

(Under Organization) 

FELLOW AWARD. To consider qualifications of Active members as candidates for eleva- 
tion to Fellow, and to submit such nominations to the Board of Governors. 

D/E. HYNDMAN, Chairman 

342 Madison Ave. 
New York 17, N. Y. 





FILM PROJECTION PRACTICE. To make recommendations and prepare specifications 
for the operation, maintenance and servicing of motion picture projection equipment, projection 
rooms, film storage facilities, stage arrangement, screen dimensions and placement, and main- 
tenance of loudspeakers to improve the quality of reproduced sound and the quality of the 
projected picture in the theater. 

G. T. LORANCE, Chairman 

63 Bedford Road 
Pleasantville, N. Y. 











HISTORICAL AND MUSEUM. To collect facts and assemble data relating to the historical 
development of the motion picture industry, to encourage pioneers to place their work on record 
in the form of papers for publication in the JOURNAL, and to place in suitable depositories equip- 
ment pertaining to the industry. 

(Under Organization) 

HONORARY MEMBERSHIP. To diligently search for candidates who through their 
basic inventions or outstanding accomplishments have contributed to the advancement of the 
motion picture industry and are thus worthy of becoming Honorary members of the Society. 

H. W. REMERSCHEID, Chairman 

716 N. LaBrea St. 
Hollywood, Calif. 



Advisory Member. 

April 1947 



JOURNAL AWARD. To recommend to the Board of Governors the author or authors of 
the most outstanding paper originally published in the JOURNAL during the preceding calendar 
year to receive the Society's Journal Award. 

J. I. CRABTREE, Chairman 

Research Laboratories 
Eastman Kodak Company 
Rochester 4, N. Y. 



LABORATORY PRACTICE. To make recommendations and prepare specifications for the 
operation, maintenance, and servicing of motion picture printers, processing machines, inspec- 
tion projectors, splicing machines, film cleaning and treating equipment, rewinding equipment, 
any type of film handling accessories, methods, and processes which offer increased efficiency 
and improvement in the photographic quality of the final print. 

H. E. WHITE, Temporary Chairman 

342 Madison Ave. 
New York 17, N. Y. 







MEMBERSHIP AND SUBSCRIPTION. To solicit new members, obtain non member sub- 
scriptions for the JOURNAL, and to arouse general interest in the activities of the Society and its 


L. E. JONES, Chairman 
427 West 42d St. 
New York 18, N. Y. 











0. F. NEU 





16 Mm 


G. C. MISENER, Chairman 

6424 Santa Monica Blvd. 
Hollywood 38, Calif. 


C. R. WOOD, SR. 






NOMINATIONS. To recommend nominations to the Board of Governors for annual election 
of officers and governors. 

E. A. WILLIFORD, Chairman 

230 Park Ave. 
New York 17, N. Y. 




PAPERS. To solicit papers, and provide the program for semi-annual conventions, and make 
available to local sections for their meetings papers presented at national conventions. 

G. A. CHAMBERS, Chairman 

343 State St. 
Rochester 4, N. Y. 

HERBERT BARNETT, Vice-Chairman N. L. SIMMONS, Vice- Chair man 

92 Gold St. 6706 Santa Monica Blvd. 

New York 7, N. Y. Hollywood 38, Calif. 

R. T. VAN NIMAN, Vice-Chairman H. S. WALKER, Vice-Chairman 

4431 W. Lake St. 1620 Notre Dame St., W. 

Chicago 24, 111. Montreal, Canada 





PRESERVATION OF FILM. To make recommendations and prepare specifications on 
methods of treating and storage of motion picture film for active, archival, and permanent 
record purposes, so far as can be prepared within both the economic and historical value of the 

J. G. BRADLEY, Chairman 

The Library of Congress 
Washington 25, D. C. 





PROCESS PHOTOGRAPHY. To make recommendations and prepare specifications on 
motion picture optical printers, process projectors (background process), matte processes, 
special process lighting technique, special processing machines, miniature set requirements, 
special effects devices, and the like, that will lead to improvement in this phase of the production 

(Under Organization) 

PROGRESS. To pre'pare an annual report on progress in the motion picture industry. 

(Under Organization) 

PROGRESS MEDAL AWARD. To recommend to the Board of Governors a candidate who 
by his inventions, research, or development has contributed in a significant manner to the 
advancement of motion picture technology, and is deemed worthy of receiving the Progress 
Medal Award of the Society. 

F. E. CARLSON, Chairman 

Nela Park 
Cleveland 12, Ohio 



PUBLICITY. To assist the Convention Vice-President in the release of publicity material 
concerning the Society's semi-annual technical conventions. 

RCA Victor Division 
Radio Corp. of America 
Camden, N. J. 



* Advisory Member. 

April 1947 



SCREEN BRIGHTNESS. To make recommendations, prepare specifications, and test 
methods for determining and standardizing the brightness of the motion picture screen image 
at various parts of the screen, and for special means or devices in the projection room adapted 
to the control or improvement of screen brightness. 

E. R. GEIB, Chairman 

National Carbon Company, Inc. 
Post or ia Works 
Fostoria, Ohio 

*V. A. SlLARD 




16-MM AND 8-MM MOTION PICTURES (Formerly Nontheatrical Equipment). To 
make recommendations and prepare specifications for 16-mm and 8-mm cameras, 16-mm 
sound recorders and sound recording practices, 16-mm and 8-mm printers and other film labo- 
ratory equipment and practices, 16-mm and 8-mm projectors, splicing machines, screen dimen- 
sions and placement, loudspeaker output and placement, preview or theater arrangements, 
test films, and the like, which will improve the quality of 16-mm and 8-mm motion pictures. 

D. F. LYMAN, Chairman 

333 State St. 
Rochester 4, N. Y. 














SOUND. To make recommendations and prepare specifications for the operation, mainte- 
nance, and servicing of motion picture film, sound recorders, rerecorders, and reproducing 
equipment, methods of recording sound, sound film processing, and the like, to obtain means of 
standardizing procedures that will result in the production of better uniform quality sound in 
the theater. 

J. G. FRAYNE, Chairman 

6601 Romaine St. 
Hollywood 38, Calif. 














A. G. 










STANDARDS. To constantly survey all engineering phases of motion picture production, 
distribution, and exhibition, to make recommendations and prepare specifications that may 
become proposals for SMPE Recommended Practices and/or American Standards. This 
Committee should carefully follow the work of all other committees on engineering and may 
request any committee to investigate and prepare a report on the phase of motion picture 
engineering to which it is assigned. 

F. T. BOWDITCH, Chairman 

Box 6087 
Cleveland 1, Ohio 





* Advisory Member. 




(See next page.) 



Vol 48, No. 4 



D. B. JOY 



















STUDIO LIGHTING. To make recommendations and prepare specifications for the 
operation, maintenance, and servicing of all types of studio and outdoor auxiliary lighting 
equipment, tungsten light and carbon arc sources, lighting effect devices, diffusers, special light 
screens, etc., to increase the general engineering knowledge of the art. 


C. W. HANDLE Y, Chairman 
I960 West 84th St. 
Los Angeles 44, Calif. 



TELEVISION. To study the television art with special reference to the technical inter- 
relationships of the television and motion picture industries, and to make recommendations 
and prepare specifications for equipment, methods, and nomenclature designed to meet the 
special problems encountered at the junction of the two industries. 

D. R. WHITE, Chairman 

Redpath Laboratories 

E. I. du Pont de Nemours & Co. 
Parlin. N. J. 











TELEVISION PROJECTION PRACTICE. To make recommendations and prepare speci- 
fications for the construction, installation, operation, maintenance, and servicing of equipment 
for projecting television pictures in the motion picture theater, as well as projection room 
arrangements necessary for such equipment, and such picture-dimensional and screen-charac- 
teristic matters as may be involved in high-quality theater television presentation. 

P. J. LARSEN, Chairman 

1401 Sheridan St., N. W. 
Washington 11, D. C. 

F. E. CAHILL, JR., Vice- Chairman 

321 West 44th St. 
New York 18, N. Y. 










JAMES FRANK, JR., Secretary 

356 West 44th St. 
New York 18. N. Y. 









* Advisory Member. 


TEST FILM QUALITY. To supervise, inspect, and approve all print quality control of 
sound and picture test films prepared by any committee on engineering before the prints are 
released by the Society for general practical use. 

F. S. BERMAN, Chairman 

111-14 76th Ave. 
Forest Hills, N. Y. 


mendations and prepare specifications on engineering methods and equipment of motion picture 
theaters in relation to their contribution to the physical comfort and safety of patrons, so far 
as can be enhanced by correct theater design, construction, and operation of equipment. 


1501 Broadway 
New York 18, N. Y. 







American Documentation Institute J. E. ABBOTT 

American Standards Association: 

Sectional Committee on Standardization of Letter 
Symbols and Abbreviations for Science and 

Engineering, Z10 S. L. CHERTOK 

Sectional Committee on Motion Pictures, Z22. .C. R. KEITH, Chm. 

A. N. GOLDSMITH, Hon.Chm. 



Sectional Committee on Acoustical Measurements 

and Terminology, Z24 F. C. SCHMID 

Sectional Committee on Photography, Z38 J. I. CRABTREE 

Standards Council, ASA Member-Bodies D. E. HYNDMAN 

Inter-Society Color Council R. M. EVANS, Chm. 





National Fire Protection Association A. S. DICKINSON 

Radio Technical Planning Board P. J. LARSBN 


* Advisory Member: t Alternate. 



Article I 


The name of this association shall be SOCIETY OF MOTION PICTURE 

Article II 


Its objects shall be: Advancement in the theory and practice of motion pic- 
ture engineering and the allied arts and sciences, the standardization of the equip- 
ment, mechanisms, and practices employed therein, the maintenance of a high 
professional standing among its members, and Ihe dissemination of scientific 
knowledge by publication. 

Article III 


Any person of good character may be a member in any grade for which he is 

Article IV 


The officers of the Society shall be a President, a Past-President, an Executive 
Vice-President, an Engineering Vice-President, an Editorial Vice-President, a 
Financial Vice-President, a Convention Vice-President, a Secretary, and a 

The term of office of all elected officers shall be for a period of two years. Of 
the Engineering, Editorial, Financial, and Convention Vice-Presidents, and the 
Secretary, and the Treasurer, three shall be elected alternately each year, or until 
their successors are chosen. The President shall not be immediately eligible to 
succeed himself in office. Under such conditions as set forth in the By-Laws the 
office of Executive Vice-President may be vacated before the expiration of his 

Article V 

Board of Governors 

The Board of Governors shall consist of the President, the Past-President, the 
five Vice-Presidents, the Secretary, the Treasurer, the Section Chairmen and 

* Corrected to Apr. 1, 1947. 


ten elected governors. Five of these governors shall be resident in the area operat- 
ing under Pacific and Mountain time, and five of the governors shall be resident 
in the area operating under Central and Eastern time. Two of the governors 
from the Pacific area and three of the governors from the Eastern area shall be 
elected in the odd-numbered years, and three of the governors in the Pacific area 
and two of the governors in the Eastern area shall be elected in the even-numbered 
years. The term of office of all elected governors shall be for a period of two 

Article VI 


There shall be an annual meeting, and such other meetings as stated in the 

Article VII 


This Constitution may be amended as follows: Amendments shall be approved 
by the Board of Governors, and shall be submitted for discussion at any regular 
members' meeting. The proposed amendment and complete discussion then shall 
be submitted to the entire Active, Fellow, and Honorary membership, together 
with letter ballot as soon as possible after the meeting. Two-thirds of the vote 
cast within sixty days after mailing shall be required to carry the amendment. 


By-Law I 


Sec. 1. The membership of the Society shall consist of Honorary members, 
Fellows, Active members, Associate members, Student members, and Sustaining 

An Honorary member is one who has performed eminent services in the ad- 
vancement of motion picture engineering or in the allied arts. An Honorary 
member shall be entitled to vote and to hold any office in the Society. 

A Fellow is one who shall not be less than thirty years of age and who shall 
comply with the requirements of either (a) or (6) for Active members and, in 
addition, shall by his proficiency and contributions have attained to an out- 
standing rank among engineers or executives of the motion picture industry. 
A Fellow shall be entitled to vote and to hold any office in the Society. 

An Active member is one who shall be not less than 25 years of age, and shall 
be (a) a motion picture engineer by profession. He shall have been engaged in 
the practice of his profession for a period of at least three years, and shall have 
taken responsibility for the design, installation, or operation of systems or ap- 
paratus pertaining to the motion picture industry; (6) a person regularly em- 
ployed in motion picture or closely allied work, who by his inventions or pro- 
ficiency in motion picture science or as an executive of a motion picture enterprise 
of large scope, has attained to a recognized standing in the motion picture industry. 


In case of such an executive, the applicant must be qualified to take full charge 
of the broader features of motion picture engineering involved in the work under 
his direction. 

An Active member is privileged to vote and to hold any office in the Society. 

An Associate member is one who shall be not less than 18 years of age, and shall 
be a person who is interested in or connected with the study of motion picture 
technical problems or the application of them. An Associate member is not privi- 
leged to vote, to hold office or to act as chairman of any committee, although he 
may serve upon any committee to which he may be appointed; and, when so 
appointed, shall be entitled to the full voting privileges of a committee member. 

A Student member is any person registered as a student, graduate or under- 
graduate, in a college, university, or educational institution, pursuing a course of 
studies in science or engineering that evidences interest in motion picture tech- 
nology. Membership in this grade shall not extend more than one year beyond 
the termination of the student status described above. A Student member shall 
have the same privileges as an Associate member of the Society. 

A Sustaining member is an individual, a firm, or corporation contributing sub- 
stantially to the financial support of the Society. 

Sec. 2. All applications for membership or transfer, except for Honorary or 
Fellow membership, shall be made on blank forms provided for the purpose, and 
shall give a complete record of the applicant's education and experience. Honor- 
ary and Fellow membership may not be applied for. 

Sec. 3. (a) Honorary membership may be granted upon recommendation 
of the Board of Governors when confirmed by a four-fifths majority vote of the 
Honorary members, Fellows, and Active members present at any regular meeting 
of the Society. An Honorary member shall be exempt from all dues. 

(b) Fellow membership may be granted upcn recommendation of the Fellow 
Award Committee, when confirmed by a three-fourths majority vote of the 
Board of Governors. Nominations for Fellow shall be made from the Active 

(c) Applicants for Active membership shall give as references at least one mem- 
ber of Active or of higher grade in good standing. Applicants shall be elected 
to membership by the unanimous approval of the entire membership of the ap- 
propriate Admissions Committee. In the event of a single dissenting vote or 
failure of any member of the Admissions Committee to vote, this application shall 
be referred to the Board of Governors, in which case approval of at least three- 
fourths of the Board of Governors shall be required. 

(d) Applicants for Associate membership shall give as references one member 
of the Society in good standing, or two persons not members of the Society who 
are associated with the industry. Applicants shall be elected to membership 
by approval of a majority of the appropriate Admissions Committee. 

(e) Applicants for Student membership shall give as reference the head of the 
department of the institution he is attending, this faculty member not necessarily 
being a member of the Society. 

By-Law II 


Sec. 1. An officer or governor shall be an Honorary, a Fellow, or an Active 


Sec. 2. Vacancies in the Board of Governors shall be filled by the Board of 
Governors until the annual meeting of the Society. 

By-Law III 

Board of Governors 

Sec. 1. The Board of Governors shall transact the business of the Society 
between members' meetings, and shall meet at the call of the President, with the 
proviso that no meeting shall be called without at least seven (7) days' prior 
notice, stating the purpose of the meeting, to all members of the Board by letter or 
by telegram. 

Sec. 2. Nine members of the Board of Governors shall constitute a quorum 
at all meetings. 

Sec. 3. When voting by letter ballot, a majority affirmative vote of the total 
membership of the Board of Governors shall carry approval, except as otherwise 

Sec. 4. The Board of Governors, when making nominations to fill vacancies 
in offices or on the Board, shalfendeavor to nominate persons who in the aggregate 
are representative of the various branches or organizations of the motion picture 
industry to the end that there shall be no substantial predominance upon the 
Board, as the result of its own action, of representatives of any one or more 
branches or organizations of the industry. 

By-Law IV 


Sec. 1. All committees, except as otherwise specified, shall be appointed by the 

Sec. 2. All committees shall be appointed to act for the term served by the 
officer who shall appoint the committees, unless their appointment is sooner ter- 
minated by the appointing officer. 

Sec. 3. Chairmen of the committees shall not be eligible to serve in such ca- 
pacity for more than two consecutive terms. 

Sec. 4. Standing committees of the Society shall be as follows to be appointed 
as designated: 

(a) Appointed by the President and confirmed by the Board of Governors 

Progress Medal Award Committee 
Journal Award Committee 
Honorary Membership Committee 
Fellow Award Committee 
Admissions Committees 

(Atlantic Coast Section) 

(Pacific Coast Section) 
European Advisory Committee 

(b) Appointed by the Engineering Vice- President 

Sound Committee 
Standards Committee 


Studio Lighting Committee 

Color Committee 

Theater Engineering Committee 

Exchange Practice Committee 

Nontheatrical Equipment Committee 

Television Committee 

Test Film Quality Committee 

Laboratory Practice Committee 

Cinematography Committee 

Process Photography Committee 

Preservation of Film Committee 

(c) Appointed by the Editorial Vice- President 

Board of Editors 
Papers Committee 
Progress Committee 
Historical Committee 
Museum Committee 

(d) Appointed by the Convention Vice- President- 

Publicity Committee 

Convention Arrangements Committee 

Apparatus Exhibit Committee 

(e) Appointed by the Financial Vice- President 

Membership and Subscription Committee 


Sec. 5. Two Admissions Committees, one for the Atlantic Coast Section and 
one for the Pacific Coast Section, shall be appointed. The former Committee 
shall consist of a Chairman and six Fellow or Active members of the Society re- 
siding in the metropolitan area of New York, of whom at least four shall be mem- 
bers of the Board of Governors. 

The latter Committee shall consist of a Chairman and four Fellow or Active 
members of the Society residing in the Pacific Coast area, of whom at least three 
shall be members of the Board of Governors. 

By-Law V 


Sec. 1. The location of each meeting of the Society shall be determined by the 
Board of Governors. 

Sec. 2. Only Honorary members, Fellows, and Active members shall be en- 
titled to vote. 

Sec. 3. A quorum of the Society shall consist in number of one-fifteenth of 
the total number of Honorary members, Fellows, and Active members as listed 
in the Society's records at the close of the last fiscal year. 

Sec. 4. The fall convention shall be the annual meeting. 

Sec. 5. Special meetings may be called by the President and upon the request 
of any three members of the Board of Governors not including the President. 

Sec. 6. All members of the Society in any grade shall have the privilege of dis- 
cussing technical material presented before the Society or its Sections. 


By-Law VI 

Duties of Officers 

Sec. 1. The President shall preside at all business meetings of the Society and 
shall perform the duties pertaining to that office. As such he shall be the chief 
executive of the Society, to whom all other officers shall report. 

Sec. 2. In the absence of the President, the officer next in order as listed in 
Article IV of the Constitution shall preside at meetings and perform the duties of 
the President. 

Sec. 3. The five Vice-Presidents shall perform the duties separately enumerated 
below for each office, or as defined by the President: 

(a) The Executive Vice-President shall represent the President in such geo- 
graphical areas of the United States as shall be determined by the Board of 
Governors and shall be responsible for the supervision of the general affairs of the 
Society in such areas, as directed by the President of the Society. Should the 
President or Executive Vice-President remove his residence from the geographical 
area (Atlantic Coast or Pacific Coast) of the United States in which he resided at 
the time of his election, the office of Executive Vice-President shall immediately 
become vacant and a new Executive Vice-President elected by the Board of 
Governors for the unexpired portion of the term, the new Executive Vice-President 
to be a resident of that part of the United States from which the President or 
Executive Vice-President has just moved. 

(&) The Engineering Vice-President shall appoint all technical committees. He 
shall be responsible for the general initiation, supervision, and coordination of 
the work in and among these committees. He may act as Chairman of any com- 
mittee or otherwise be a member ex-officio. 

(c) The Editorial Vice-President shall be responsible for the publication of the 
Society's JOURNAL and all other technical publications. He shall pass upon the 
suitability of the material for publication, and shall cause material suitable for 
publication to be solicited as may be needed. He shall appoint a Papers Com- 
mittee and an Editorial Committee. He may act as Chairman of any committee 
or otherwise be a member ex-officio. 

(d} The Financial Vice-President shall be responsible for the financial opera- 
tions of the Society, and shall conduct them in accordance with budgets approved 
by the Board of Governors. He shall study the costs of operation and the income 
possibilities to the end that the. greatest service may be rendered to the members 
of the Society within the available funds. He shall submit proposed budgets to 
the Board. He shall appoint at his discretion a Ways and Means Committee, a 
Membership Committee, a Commercial Advertising Committee, and such other 
committees within the scope of his work as may be needed. He may act as Chair- 
man of any of these committees or otherwise be a member ex-officio. 

(e} The Convention Vice-President shall be responsible for the national con- 
ventions of the Society. He shall appoint a Convention Arrangements Com- 
mittee, an Apparatus Exhibit Committee, and a Publicity Committee. He may 
act as Chairman of any committee, or otherwise be a member ex-officio. 

Sec. 4. The Secretary shall keep a record of all meetings; he shall conduct the 
correspondence relating to his office, and shall have the care and custody of 
records, and the seal of the Society. 

Sec. 5. The Treasurer shall have charge of the funds of the Society and dis- 
burse them as and when authorized by the Financial Vice-President. He shall 


make an annual report, duly audited, to the Society, and a report at such other 
times as may be requested. He shall be bonded in an amount to be determined 
by the Board of Governors and his bond filed with the Secretary. 

Sec. 6. Each officer of the Society, upon the expiration of his term of office, 
shall transmit to his successor a memorandum outlining the duties and policies 
of his office. 

By-Law VII 


Sec. 1. All officers and governors shall be elected to their respective offices 
by a majority of ballots cast by the Active, Fellow, and Honorary members in the 
following manner: 

Not less than three months prior to the annual fall convention, the Board of 
Governors shall nominate for each vacancy several suitable candidates. Nomi- 
nations shall first be presented by a Nominating Committee appointed by the 
President, consisting of nine members, including a Chairman. The committee 
shall be made up of two Past-Presidents, three members of the Board of Governors 
not up for election, and four other Active, Fellow, or Honorary members, not 
currently officers or governors of the Society. Nominations shall be made by 
three-quarters affirmative vote of the total Nominating Committee. Such nomi- 
nations shall be final unless any nominee is rejected by a three-quarters vote of 
the Board of Governors present and voting. 

The Secretary shall then notify these candidates of their nomination. From 
the list of acceptances, not more than two names for each vacancy shall be se- 
lected by the Board of Governors and placed on a letter ballot. A blank space 
shall be provided on this letter ballot under each office, in which space the names 
of any Active, Fellow, or Honorary members other than those suggested by the 
Board of Governors may be voted for. The balloting shall then take place. 

The ballot shall be enclosed in a blank envelope which is enclosed in an outer 
envelope bearing the Secretary's address and a space for the member's name and 
address. One of these shall be mailed to each Active, Fellow, and Honorary 
member of the Society, not less than forty days in advance of the annual fall con- 

The voter shall then indicate on the ballot one choice for each office, seal the 
ballot in the blank envelope, place this in the envelope addressed to the Secretary, 
sign his name and address on the latter, and mail it in accordance with the in- 
structions printed on the ballot. No marks of any kind except those above pre- 
scribed shall be placed upon the ballots or envelopes. Voting shall close seven 
days before the opening session of the annual fall convention. 

The sealed envelope shall be delivered by the Secretary to a Committee of 
Tellers appointed by the President at the annual fall convention. This com- 
mittee shall then examine the return envelopes, open and count the ballots, and 
announce the results of the election. 

The newly elected officers and governors of the general Society shall take office 
on January 1st following their election. 

By-Law VIII 

Dues and Indebtedness 

Sec. 1. The annual dues shall be fifteen dollars ($15) for Fellows and Active 
members, ten dollars ($10) for Associate members, and five dollars ($5) for 


Student members, payable on or before January 1st of each year. Current or 
first year's dues for new members in any calendar year shall be at the full annual 
rate for those notified of acceptance in the Society on or before June 30th; one- 
half the annual rate for those notified of acceptance in the Society on or after 
July 1st. 

Sec. 2. (a) Transfer of membership to a higher grade may be made at any 
time. If the transfer is made on or before June 30th the annual dues of the 
higher grade is required. If the transfer is made on or after July 1st and the 
member's dues for the full year has been paid, one-half of the annual dues of the 
higher grade is payable less one-half the annual dues of the lower grade. 

(6) No credit shall be given for annual dues in a membership transfer from a 
higher to a lower grade, and such transfers shall take place on January 1st of each 

(c) The Board of Governors upon their own initiative and without a transfer 
application may elect, by the approval of at least three-fourths of the Board, 
any Associate or Active member for transfer to any higher grade of membership. 

Sec. 3. Annual dues shall be paid in advance. A new member who has not 
paid dues in advance shall be notified of admittance but shall not receive the 
JOURNAL and is not in good standing until initial dues are paid. All Honorary 
members, Fellows, and Active members in good standing, as defined in Section 5, 
may vote or otherwise participate in the meetings. 

Sec. 4. Members shall be considered delinquent whose annual dues for the 
year remain unpaid on February 1st. The first notice of delinquency shall be 
mailed February 1st. The second notice of delinquency shall be mailed, if neces- 
sary, on March 1st, and shall include a statement that the member's name will be 
removed from the mailing list for the JOURNAL and other publications of the 
Society before the mailing of the April issue of the JOURNAL. Members who are 
in arrears of dues on June 1st, after two notices of such delinquency have been 
mailed to their last address of record, shall be notified their names have been re- 
moved from the mailing list and shall be warned unless remittance is received on or 
before August 1st, their names shall be submitted to the Board of Governors for 
action at the next meeting. Back issues of the JOURNAL shall be sent, if available, 
to members whose dues have been paid prior to August 1st. 

Sec. 5. (a) Members whose dues remain unpaid on October 1st may be dropped 
from the rolls of the Society by majority vote and action of the Board, or the 
Board may take such action as it sees fit. 

(&) Anyone who has been dropped from the rolls of the Society for nonpay- 
ment of dues shall, in the event of his application for reinstatement, be considered 
as a new member. 

(c) Any member may be suspended or expelled for cause by a majority vote of 
the entire Board of Governors; provided he shall be given notice and a copy in 
writing of the charges preferred against him, and shall be afforded opportunity 
to be heard ten days prior to such action. 

Sec. 6. The provisions of Sections 1 to 4, inclusive, of this By-Law VIII given 
above may be modified or rescinded by action of the Board of Governors. 

By-Law IX 

Sec. 1. The emblem of the Society shall be a facsimile of a four-hole film reel 


with the letter 5 in the upper center opening, and the letters M, P, and E, in the 
three lower openings, respectively. The Society's emblem may be worn by 
members only. 

By-Law X 


Sec. 1. Papers read at meetings or submitted at other times, and all material 
of general interest shall be submitted to the Editorial Board, and those deemed 
worthy of permanent record shall be printed in the JOURNAL. A copy of each 
issue shall be mailed to each member in good standing to his last address of record. 
Extra copies of the JOURNAL shall be printed for general distribution and may be 
obtained from the General Office on payment of a fee fixed by the Board of 

By-Law XI 

Local Sections 

Sec. 1. Sections of the Society may be authorized in any state or locality where 
the Active, Fellow, and Honorary membership exceeds 20. The geographic 
boundaries of each Section shall be determined by the Board of Governors. 

Upon written petition, signed by 20 or more Active members, Fellows, and Hon- 
orary members, for the authorization of a Section of the Society, the Board of 
Governors may grant such authorization. 

Section Membership 

Sec. 2. All members of the Society of Motion Picture Engineers in good stand- 
ing residing in that portion of any country set apart by the Board of Governors 
tributary to any local Section shall be eligible for membership in that Section, and 
when so enrolled they shall be entitled to all privileges that such local Section may, 
under the General Society's Constitution and By-Laws, provide. 

Any member of the Society in good standing shall be eligible for nonresident 
affiliated membership of any Section under conditions and obligations prescribed 
for the Section. An affiliated member shall receive all notices and publications of 
the Section but he shall not be entitled to vote at sectional meetings. 

Sec. 3. Should the enrolled Active, Fellow, and Honorary membership of a 
Section fall below 20, or should the technical quality of the presented papers fall 
below an acceptable level, or the average attendance at meetings not warrant the 
expense of maintaining the organization, the Board of Governors may cancel its 

Section Officers 

Sec. 4. The. officers of each Section shall be a Chairman and a Secretary- 
Treasurer. The Section chairmen shall automatically become members of the 
Board of Governors of the General Society, and continue in such positions for the 
duration of their terms as chairmen of the local Sections. Each Section officer 
shall hold office for one year, or until his successor is chosen. 

Section Board of Managers 

Sec. 5. The Board of Managers shall consist of the Section Chairman, the 
Section Past-Chairman, the Section Secretary-Treasurer, and six Active, Fellow, or 


Honorary members. Each manager of a Section shall hold office for two years, 
or until his successor is chosen. 

Section Elections 

Sec. 6. The officers and managers of a Section shall be Active, Fellow, or 
Honorary members of the General Society. All officers and managers shall be 
elected to their respective offices by a majority of ballots cast by the Active, Fel- 
low, and Honorary members residing in the geographical area covered by the 

Not less than three months prior to the annual fall convention of the Society, 
nominations shall be presented to the Board of Managers of the Section by a 
Nominating Committee appointed by the Chairman of the Section, consisting of 
seven members, including a chairman. The Committee shall be composed of the 
present Chairman, the Past-Chairman, two other members of the Board of Man- 
agers not up for election, and three other Active, Fellow, or Honorary members of 
the Section not currently officers or managers of the Section. Nominations shall 
be made by a three-quarters affirmative vote of the total Nominating Committee. 
Such nominations shall be final, unless any nominee is rejected by a three-quarters 
vote of the Board of Managers, and in the event of such rejection the Board of 
Managers will make its own nomination. 

The Chairman of the Section shall then notify these candidates of their nomi- 
nation. From the list of acceptances, not more than two names for each vacancy 
shall be selected by the Board of Managers and placed on a letter ballot. A blank 
space shall be provided on this letter ballot under' each office, in which space the 
names of any Active, Fellow, or Honorary members other than those suggested 
by the Board of Managers may be voted for. The balloting shall then take place. 

The ballot shall be enclosed in a blank envelope which is enclosed in an outer 
envelope bearing the local Secretary-Treasurer's address and a space for the 
member's name and address. One of these shall be mailed to each Active, Fellow, 
and Honorary member of the Society residing in the geographical area covered by 
the Section, not less than forty days in advance of the annual fall convention. 

The voter shall then indicate on the ballot one choice for each office, seal the 
ballot in the blank envelope, place this in the envelope addressed to the Secretary- 
Treasurer, sign his name and address on the latter, and mail it in accordance with 
the instructions printed on the ballot. No marks of any kind except those above 
prescribed shall be placed upon the ballots or envelopes. Voting shall close seven 
days before the opening session of the annual fall convention. 

The sealed envelopes shall be delivered by the Secretary-Treasurer to his 
Board of Managers at a duly called meeting. The Board of Managers shall then 
examine the return envelopes, open and count the ballots, and announce the 
results of the election. 

The newly elected officers and managers shall take office on January 1st follow- 
ing their election. 

Section Business 

Sec. 7. The business of a Section shall be conducted by the Board of Managers. 

Section Expenses 

Sec. 8. (a) As early as possible in the fiscal year, the Secretary-Treasurer of 
each Section shall submit to the Board of Governors of the Society a budget of 
expenses for the year. 


(&) The Treasurer of the General Society may deposit with each Section Secre- 
tary-Treasurer a sum of money, the amount to be fixed by the Board of Governors, 
for current expenses. 

(c) The Secretary-Treasurer of each Section shall send to the Treasurer of the 
General Society, quarterly or on demand, an itemized account of all expenditures 
incurred during the preceding interval. 

(d) Expenses other than those enumerated in the budget, as approved by the 
Board of Governors of the General Society, shall not be payable from the general 
funds of the Society without express permission from the Board of Governors. 

(e} A Section Board of Managers shall defray all expenses of the Section not 
provided for by the Board of Governors, from funds raised locally by donation, 
or fixed annual dues, or by both. 

(/) The Secretary of the General Society shall, unless otherwise arranged, supply 
to each Section all stationery and printing necessary for the conduct of its business. 

Section Meetings 

Sec. 9. The regular meetings of a Section shall be held in such places and at 
such hours as the Board of Managers may designate. 

The Secretary-Treasurer of each Section shall forward to the Secretary of the 
General Society, not later than five days after a meeting of a Section, a statement 
of the attendance and of the business transacted. 

. Section Papers 

Sec. 10. Papers shall be approved by the Section's Papers Committee previ- 
ously to their being presented before a Section. Manuscripts of papers presented 
before a Section, together with a report of the discussions and the proceedings of 
the Section meetings, shall be forwarded promptly by the Section Secretary- 
Treasurer to the Secretary of the General Society. Such material may, at the dis- 
cretion of the Board of Editors of the General Society, be printed in the Society's 

Constitution and By-Laws 

Sec. 11. Sections shall abide by the Constitution and By-Laws of the Society 
and conform to the regulations of the Board of Governors. The conduct of Sec- 
tions shall always be in conformity with the general policy of the Society as fixed 
by the Board of Governors. 

By-Law XII 


Sec. 1 . These By-Laws may be amended at any regular meeting of the Society 
by the affirmative vote of two-thirds of the members present at a meeting who 
are eligible to vote thereon, a quorum being present, either on the recommendation 
of the Board of Governors or by a recommendation. to the Board of Governors 
signed by any ten members of Active or higher grade, provided that the proposed 
amendment or amendments shall have been published in the JOURNAL of the 
Society, in the issue next preceding the date of the stated business meeting of the 
Society at which the amendment or amendments are to be acted upon. 

Sec. 2. In the event that no quorum of the voting members is present at the 
time of the meeting referred to in Section 1 , the amendment or amendments shall 


be referred for action to the Board of Governors. The proposed amendment or 
amendments then become a part of the By-Laws upon receiving the affirmative 
vote of three-quarters of the Board of Governors. 

By-Law XIII 

Student Chapters 

Sec. 1. Student Chapters of the Society may be authorized in any college, 
university, or technical institute of collegiate standing. 

Upon written petition, signed by twelve or more Society members, or applicants 
for Society membership, and the Faculty Adviser, for the authorization of a 
Student Chapter, the Board of Governors may grant such authorization. 

Chapter Membership 

Sec. 2. All members of the Society of Motion Picture Engineers in good 
standing who are attending the designated educational institution shall be eligible 
for membership in the Student Chapter, and when so enrolled they shall be 
entitled to all privileges that such Student Chapter may, under the General 
Society's Constitution and By-Laws, provide. 

Sec. 3. Should the membership of the Student Chapter fall below ten, or 
should the technical quality of the presented papers fall below an acceptable 
level, or the average attendance at meetings not warrant the expense of maintain- 
ing the organization, the Board of Governors may cancel its authorization. 

Chapter Officers 

Sec. 4. The officers of each Student Chapter shall be a Chairman and a 
Secretary-Treasurer. Each Chapter officer shall hold office for one year, or until 
his successor is chosen. Officers shall be chosen in May to take office at the be- 
ginning of the following school year. The procedure for holding elections shall be 
prescribed in Administrative Practices. 

Faculty Adviser 

Sec. 5. A member of the faculty of the same educational institution shall be 
designated by the Board of Governors as Faculty Adviser. It shall be his duty to 
advise the officers on the conduct of the Chapter and to approve all reports to the 
Secretary and the Treasurer of the Society. 

Chapter Expenses 

Sec. 6. The Treasurer of the General Society may deposit with each Chapter 
Secretary-Treasurer a sum of money, the amount to be fixed by the Board of 
Governors. The Secretary -Treasurer shall send to the Treasurer of the General 
Society at the end of each school year an itemized account of all expenditures 
incurred during that period. 

Chapter Meetings 

Sec. 7. The Chapter shall hold at least four meetings per year. The Secre- 
tary-Treasurer shall forward to the Secretary of the General Society at the end 
of each school year a report of the meetings for that year, giving the subject, 
speaker, and approximate attendance for each meeting. 


In accordance with the provisions of Administrative Practices of the So- 
ciety, the regulations for procedure in granting the Journal Award and the Prog- 
ress Medal Award, a list of the names of previous recipients, and the reasons 
therefor, are published annually in the JOURNAL as follows : 


The Journal Award Committee shall consist of five Fellows or Active members 
of the Society, appointed by the President and confirmed by the Board of Gover- 
nors. The Chairman of the Committee shall be designated by the President. 

At the fall convention of the Society a Journal Award Certificate shall be pre- 
sented to the author or to each of the authors of the most outstanding paper 
originally published in the JOURNAL of the Society during the preceding calendar 

Other papers published in the JOURNAL of the Society may be cited for Honorable 
Mention at the option of the Committee, but in any case should not exceed five in 

The Journal Award shall be made on the basis of the following qualifications : 

(1) The paper must deal with some technical phase of motion picture engineer- 

(2) No paper given in connection with the receipt of any other Award of the 
Society shall be eligible. 

(3) In judging of the merits of the paper, three qualities shall be considered, 
with the weights here indicated: 

(a) Technical merit and importance of material 45 per cent. 

(&) Originality and breadth of interest 35 per cent. 

(c) Excellence of presentation of the material 20 per cent. 

A majority vote of the entire Committee shall be required for the election to the 
Award. Absent members may vote in writing. 

The report of the Committee shall be presented to the Board of Governors at 
their July meeting for ratification. 

These regulations, a list of the names of those who have previously received the 
Journal Award, the year of each Award, and the titles of the papers shall be pub- 
lished annually in the April issue of the JOURNAL of the Society. In addition, the 
list of papers selected for Honorable Mention shall be published in the JOURNAL of 
the Society during the year current with the Award 

The Awards in previous years have been as follows: 

1934 P. A. Snell, for his paper entitled "An Introduction to the Experi- 
mental Study of Visual Fatigue". (Published May 1933.) 



1935 L. A. Jones and J. H. Webb, for their paper entitled "Reciprocity 
Law Failure in Photographic Exposure". (Published Sept. 1934 ) 

1936 E. W. Kellogg, for his paper entitled "A Comparison of Variable- 
Density and Variable- Width Systems". (Published Sept. 1935.) 

1937 D. B. Judd, for his paper entitled "Color Blindness and Anomalies of 
Vision". (Published June 1936.) 

1938 K. S. Gibson, for his paper entitled "The Analysis and Specification of 
Color". (Published Apr. 1937.) 

1939 H. T. Kalmus, for his paper entitled "Technicolor Adventures in 
Cinemaland". (Published Dec. 1938.) 

1940 R. R. McNath, for his paper entitled "The Surface of the Nearest 
Star". (Published Mar. 1939.) 

1941 J. G. Frayne and Vincent Pagliarulo, for their paper entitled "The 
Effects of Ultraviolet Light on Variable- Density Recording and Printing". 
(Published June 1940.) 

1942 W. J. Albersheim and Donald MacKenzie, for their paper entitled 
"Analysis of Sound-Film Drives." (Published July, 1941.) 

1943 R. R. Scoville and W. L. Bell, for their paper entitled "Design and 
Use of Noise-Reduction Bias Systems". (Published Feb. 1942; Award made 
Apr. 1944.) 

1944 J. I. Crabtree, G. T. Eaton, and M. E. Muehler, for their paper en- 
titled "Removal of Hypo and Silver Salts from Photographic Materials as 
Affected by the Composition of the Processing Solutions". (Published July 

1945 C. J. Kunz, H. E. Goldberg, and C. E. I ves, for their paper entitled 
"Improvement in Illumination Efficiency of Motion Picture Printers". (Pub- 
lished May 1944.) 

1946 R. H. Talbot, for his paper entitled "The Projection Life of Film". 
(Published Aug. 1945.) 

The present Chairman of the Journal Award Committee is J. I. Crabtree. 


The Progress Medal Award Committee shall consist of five Fellows or Active 
members of the Society, appointed by the President and confirmed by the Board 
of Governors. The Chairman of the Committee shall be designated by the 

The Progress Medal may be awarded each year to an individual in recognition 
of any invention, research, or development which, in the opinion of the Com- 
mittee, shall have resulted in a significant advance in the development of motion 
picture technology. 

Any member of the Society may recommend persons deemed worthy of the 
Award. The recommendation in each case shall be in writing and in detail as to 
the accomplishments which are thought to justify consideration. The recom- 
mendation shall be seconded in writing by any two Fellows or Active members 
of the Society, who shall set forth their knowledge of the accomplishments of the 
candidate which, in their opinion, justify consideration. 

A majority vote of the entire Committee shall be required to constitute an 
Award of the Progress Medal. Absent members may vote in writing. 

The report of the Committee shall be presented to the Board of Governors 
at their July meeting for ratification. 

The recipient of the Progress Medal shall be asked to present a photograph of 
himself to the Society and, at the discretion of the Committee, may be asked to 
prepare a paper for publication in the JOURNAL of the Society. 


These regulations, a list of the names of those who have previously received 
the Medal, the year of each Award, and a statement of the reason for the Award 
shall be published annually in the April issue of the JOURNAL of the Society. 

Previous Awards have been as follows : 

The 1935 Award was made to E. C. Wente, for his work in the field of sound 
recording and reproduction. (Citation published Dec. 1935.) 

The 1936 Award was made to C. E. K. Mees, for his work in photography. 
(Citation published Dec. 1936.) 

The 1937 Award was made to E. W. Kellogg, for his work in the field of sound 
reproduction. (Citation published Dec. 1937.) 

The 1938 Award was made to H. T. Kalmus, for his work in developing color 
motion pictures. (Citation published Dec. 1938.) 

The 1.939 Award was made to L. A. Jones, for his scientific researches in the 
field of photography. (Citation published Dec. 1939.) 

The 1940 Award was made to Walt Disney, for his contributions to motion 
picture photography and sound recording of feature and short cartoon films. 
(Citation published Dec. 1940.) 

The 1941 Award was made to G. L. Dimmick, for his development activities 
in motion picture sound recording. (Citation published Dec. 1941.) 

No Awards were made in 1942 and 1943. 

The 1944 Award was made to J. G. Capstaff, for his research and develop- 
ment of films and apparatus used in amateur cinematography. (Citation pub- 
lished Jan. 1945.) 

No Awards were made in 1945 and 1946. 

The present Chairman of the Progress Medal Award Committee is F. E. Carlson. 


Changes for Period January-December 31, 1946 

Hon. Sustg. Pel. Act. Assoc. Stu. Total 

Membership, Jan. 1, 1946 7 32 151 439 1322 15 1966 

New Members 32 116 379 54 581 

Reinstatements 13 11 23 

Less : Resignations 

Changes in Grade : 
Active to Fellow 
Associate to Active 
Active to Associate 
Student to Associate 

Membership, Dec. 31, 1946 

7 64 151 














-1 -2 




6 64 147 











' 1 


6 64 154 






Subscriptions, Jan. 1, 1946 349 

Renewals and New Subscriptions, Jan.-Dec. 1946 537 


Less : Expirations 

Subscriptions, Dec. 31, 1946 779 

* Grades: Honorary, Sustaining, Fellow, Active, Associate, and Student. 




Members' Equity, Jan. 1, 1946: 

Receipts, Jan-Dec. 1946: 
Membership Dues 
Sustaining Memberships 
Publications (Journals, Subscriptions, 

Reprints, Standards, Book, etc.} 
Test Films 
Other (Interest, etc.} 

Total Receipts 

Disbursements, Jan-Dec. 1946: 

General Office (Salaries, Rent, Supplies, 
Tel. & Tel., Equipment, Travel, 
Postage, etc.} 

Publications (Journal, Reprints, Stand- 
ards, Binder, etc.} 

*Test Films 

Dues and Fees to other organizations 

Sections (Atlantic, Midwest and Pacific) 

Committee Activities 

Other (Conventions, Awards, etc.} 

Total Disbursements 
Excess Recipts Over Disbursements, 1946: 

Accrued Interest on Savings Accounts 
Less : Adjustment on Bond for Accrued 
Interest at Purchase 

Members 1 Equity, Dec. 31, 1946: 
* Subject to Renegotiation. 














10.98 56.12 


Respectfully submitted, 
E. I. SPONABLE, Treasurer 


The cash records of the Treasurer were audited for the year ended December 
31, 1946, by Sparrow, Waymouth and Company, certified public accountants, 
New York, and are in conformity with the above report. 


Financial Vice-President 



All American Standards on motion pictures developed by the motion picture 
industry are published officially for the industry by the American Standards 
Association. The procedure used in the past was somewhat involved, but has 
been simplified in the light of experience gained in standardization during the 
war and the preceding ten years. At present, American Standards may be 
proposed by any competent individual, organization or industrial group and it 
is expected that they will substantiate their claims that such new proposals are 
desirable. Safeguards are necessary, of course, to ensure that the proposed 
standardization will not prejudice technical development in motion pictures, 
and the ASA procedure does this as well as make certain that anyone stating his 
opinions for or against any new proposal has an equal opportunity to be heard. 

The withdrawal of existing standards is as carefully supervised as the prepara- 
tion of new ones, and the same procedures are observed. An example is the 
American Recommended Practice for Motion Picture Film, Theater Sound 
Fader Setting Instructions, Z22.32-1941, which was officially approved for with- 
drawal by the ASA on March 7, 1947. Therefore, this standard is no longer 
valid and will not be considered as having industry sanction in the future. 

Sometime prior to 1941, the industry adopted the practice outlined in this 
standard, because at that time it was felt necessary to provide more than one type 
of recording for certain feature releases. Fader setting instructions to projection- 
ists were inserted as a 15-frame strip of information located in the first 20 frames 
of the synchronizing leader of every release print. Prints which had normal 
equalization and recording characteristics, were marked "Regular" prints, while 
all other prints were either "Hi-Range" or "Lo-Range". This practice has not 
been followed recently, and since no studio is now using it as outlined, the Re- 
search Council of the Academy of Motion Picture Arts and Sciences recommended 
to the ASA Sectional Committee on Motion Pictures, Z22, that it be withdrawn 
because continued existence of the published standard implied that the practice 
was still being observed. 

The Sectional Committee voted in favor of the withdrawal and on Dec. 31, 
1946, the secretary of that committee asked the SMPE Board of Governors, 
which acts as its sponsor, to transmit formally this recommendation for final 
action by the ASA Standards Council. The Board did so and official ASA 
approval of the withdrawal was announced on March 7, 1947. 

At the present time, American Standards on Motion Pictures number from 
Z22.1 through Z22.54. Two of them, Z22.1 and Z22.32, have been officially 
withdrawn leaving 52 valid standards on the current list. Of these, twenty-six 
were recently revised and published in the SMPE JOURNAL for April and Sep- 
tember 1946. They are available in complete sets, bound in a heavy loose-leaf 


binder, from the general office of the Society in the Hotel Pennsylvania, New 

The remaining twenty-six standards are now in various stages of revision, 
and as they are completed and approved will also be announced in the JOURNAL. 
Individual notices of all new standards and revisions, as well as withdrawals, will 
be sent to all who have purchased binders, so that they may keep their records 

A number of proposals for new motion picture standards have been submitted 
to the SMPE and are now being considered by various Society engineering com- 
mittees. Reports of these committees' activities are scheduled to appear in the 
JOURNAL and will give an indication of current standards work. 

Recently adopted standardization procedure of the SMPE provides for publica- 
tion of all new standards proposals in the JOURNAL in the form of a complete 
committee report outlining the past history of each new standard, the story of 
its progress through Society committees, and a review of its ultimate effect on 
on the industry. Following publication of this report, and a suitable waiting 
period of about 60 days, each new standard will go to letter ballot of the Com- 
mittee on Standards if no unfavorable comments or criticisms are received. 
However, if any serious objection to the new proposal has been raised as a result 
of this publication, the standard will go back to the committee that prepared it 
with appropriate instructions from the engineering vice-president and the chair- 
man of the Committee on Standards to assure that each serious comment receives 
thorough consideration. Then, following approval by the Committee on Stand- 
ards, the customary standardization procedures are observed and the standard 
ultimately published. 


One of the largest groups ever to attend a meeting of the Atlantic Coast Section 
of the Society turned out on March 19 to inspect the new quarters of RKO Pathe 
Studios and Pathe Film Laboratories at Park Avenue and 106th St., New York. 
Walton C. Ament, vice-president and general manager of RKO Pathe Studios, 
reviewed the history of the building in which the new studios are housed and 
described certain features of the building that make it applicable to modern 
motion picture production. Frank Wooley, chief -recording engineer, described 
the plan and production setup and facilities. 

Nick Tronolone, vice-president and general manager of Pathe Laboratories, 
discussed the organization and laboratory facilities, and explained work being 
done in the laboratories. 

Following these discussions in the Scoring Room, the audience broke up into 
small groups for an inspection tour of the studios and laboratory. A motion 
picture depicting the work of Alexander Graham Bell, produced by the studio, 
opened the meeting. An unexpectedly large attendance exceeded seating ar- 
rangements, and it was necessary to use an adjourning studio to accommodate 
the overflow. The attendance was estimated at 450. 



Dr. S. Pakswer, chief engineer of Continental Electric Company, presented 
a paper entitled "Factors Influencing the Life of Photoemissive Tubes," at the 
March 13 meeting of the Midwest Section of the Society in the Western Society 
of Engineers Hall, Chicago. Dr. Pakswer outlined the fundamental theory of 
the phototube with special reference to the S-l and S-4 types. His paper included 
numerous graphs showing the characteristics of these tubes and the time relation 
between fatigue and exposure. Microphonic effects and causes were also dis- 

The second paper on the program was presented by Marvin Camras, research 
physicist of the Armour Research Foundation, entitled "Magnetic Sound for 
Motion Pictures." Mr. Camras explained the principles of magnetic recording 
and described particularly the possibilities of using a metallic coating for a sound 
track on 35-, 16-, and 8-mm film. He elaborated on further developments and 
improvements made with this type of recording since he first presented the 
principles at the Hollywood Convention of the Society in October 1946. [His 
paper was published in the January 1947 JOURNAL Ed.] Mr. Camras concluded 
his talk with an interesting presentation of magnetic sound recording on 16-mm 

A. Shapiro, chairman of the Section, announced that the regular monthly 
meeting for April would be canceled in view of the 61st Semiannual Convention 
to be held in Chicago on April 21-25. 

We are grieved to announce the deaths of L. D. Strong, Active mem- 
ber of the Society, on April 27, 1947, in Chicago, III., and S. E. 
Hawkins, Active member of the Society, on April 24, 1947, in 


Vol 48 MAY 1947 No. 5 



Flashtubes A Potential Illuminant for Motion Pic- 
ture Photography? F. E. CARLSON 395 

Historical Development of Sound Films, Parts 3-7 


The Contribution of Theater Service to Twenty Years 
of Motion Picture Sound Progress E. S. SEELEY 423 

SMPE Honor Roll Awards : 437 

Theodore W. Case 
Edward B. Craft 
Samuel L. Warner 

Increased Light for Projection of 16-Mm Film with 
Carbon Arcs R. J. ZAVESKY AND W. W. LOZIER 447 

Radar Scope Photography R. C. BABISH 454 

A Proposed Film Lock and Identification Band 


Preservation and Postwar Utilization of U. S. Navy 
Combat Film G. L. SARCHET 476 

Current Literature 481 

Society Announcements 482 

Copyrighted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to .the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 










** President: LOREN L. RYDER, 

6451 Marathon St., Hollywood 38. 
** Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
** Executive Vice-President: EARL I. SPONABLE, 

460 West 64th St., New York 19. 
^Engineering V ice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial Vice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
^Financial Vice-President: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** ''Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
^Treasurer: E. A. BERTRAM, 
850 Tenth Ave., New York 19. 

**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 6451 Marathon St., Hollywood 38. 
*fjAMES FRANK, JR., 356 West 44th St., New York 18. 

*JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*JA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
* WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

Term expires December 31, 1947. tChairman, Atlantic Coast Section. 
**Term expires December 31, 1948. tChairman, Midwest Section. 
Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 

their annual membership dues; single copies, $1.25. Order from the Society at address above. 

A discount of ten per cent is allowed to accredited agencies on orders for subscriptions 

and single copies. 
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 

General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 

Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., 

under the Act of March 3, 1879. 


Vol 48 MAY, 1947 No. 5 



Summary. This paper presents a preliminary appraisal of flashtubes from 
the point of view of motion picture studio photography. Such sources have been 
widely and successfully used for still photography for several years. In this field the 
short duration and high intensity of the flash, its color quality and high efficiency 
have been important factors in its favor. Most of these advantages, while equally 
important in the motion picture studio, cannot necessarily be realized to the same 
degree in this field. Furthermore, many problems, the magnitude of which cannot 
be predicted at this time, appear inevitable and will undoubtedly require thorough 
analysis before a final evaluation is possible. 

Ryder, in a recent paper 1 before the Society, voiced the moderniza- 
tion desires not only of his studio, but of many others as well. The 
subject of lighting occupied a prominent place in his timely review 
of the problems of the industry, and he has suggested that the solu- 
tion to some of those problems may be found in the developments of 
World War II just as sound and radio were largely derivatives of 
World War I. Flashtubes, while predating the recent war by a con- 
siderable margin, were so improved and the scope of their usefulness 
so broadened as a result of the part they played in that conflict that 
in their present form they may be considered to some extent a 
product of World War II. It is appropriate, therefore, that they be 
critically examined at this time to determine their possible applica- 
tion to the lighting problems of the motion picture studio. 

Motion picture film is exposed on the set by a series of light im- 
pulses of short duration, and motion picture film is viewed in the 

* Presented Jan. 10, 1947, at a meeting of the Pacific Coast Section of the 
Society in Hollywood, and at the SMPE Convention in Chicago on Apr. 24, 1947. 
** General Electric Company, Lamp Department, Cleveland, Ohio. 


396 F. E. CARLSON Vol 48, No. 5 

theater in precisely the same way. The sources of illumination 
used in both instances are "continuous" in the sense that they are 
continuously emitting light and the impulses are obtained by using 
mechanical shutters which intercept, or throw away, approximately 
one-half of the available light. In so far as the mechanics of the 
operations just described are concerned, it would appear possibly 
more advantageous to use sources of intermittent light from which, 
conceivably, less light need be wasted. The flashtube is such a 
source of intermittent light. 

Types of Flashtubes. The characteristics of flashtube types 
currently available have already been described 2 ' 3 and are, there- 
fore, only briefly summarized here. A flashtube consists simply of a 

FIG. 1. Examples of straight flashtubes and a special curved tube. Straight 
tubes have been made in lengths ranging from less than 4 in. to a little more 
than 5 ft. 

gas-filled envelope containing two electrodes. In all of the flash- 
tubes currently in use, the envelope is a slender tube of glass or 
quartz with the electrodes at each end. Some types consist of 
straight or curved tubes, Fig. 1, for use in trough reflectors; in 
others the tubing is coiled in the form of a helix, Fig. 2, to produce 
relatively concentrated sources suitable for use with lenses or re- 
flectors which are surfaces of revolution. 

Flashtube Operation. The light emitted by a flashtube results 
from the discharge of a condenser, or the application of a pulse of 
energy between the electrodes. In order to avoid the damaging 
effects of high peak currents, characteristic of a condenser discharge, 
most tubes, at present, are of a type such that no switch is required 
in the discharge circuit. This is accomplished through adjustments 

May 1947 FLASHTUBES 397 

in tube design so that the tube will not flash over when full operating 
voltage is applied to the two electrodes. In this case, flashover can 
be made to occur when desired by ionizing the tube so that it be- 
comes conductive. When the impressed voltage has dropped to a 
low value, as it does near the end of a condenser-discharge cycle, the 
tube ceases to conduct, and is then ready to be flashed again. With 
this arrangement the tube may be connected continuously to the 
source of supply and thus eliminate the hazards of switch failure. 

FIG. 2. Flashtubes of the helical type are assembled with various bulb and 
base combinations to protect the user from exposed electrical parts and to 
facilitate their use in lighting equipment. Some assemblies provide for forced 
air cooling, or they may be incorporated in integral reflectors. 

lonization of tubes used as described in the preceding paragraph 
is accomplished by applying a very high voltage externally to the 
wall of the tube for a brief instant only a few microseconds at 
most. Such an ionizing pulse can be obtained from a small step-up 
transformer much like the spark coil used with car ignition systems. 
The basic elements of a typical power supply employing a condenser 
discharge are shown in Fig. 3. 

Special problems arise in the design of a power supply for repeti- 
tive operation of flashtubes. For example, in the case of condenser- 
discharge systems, if the voltage to the condenser and flash tube is 
allowed to build up too rapidly after the tube has been flashed, or if 
the interval between flashes is too brief, the tube may not have time 



Vol 48, No. 5 

to deionize and, in this event, is conductive at less than the desired 
operating voltage. This may be corrected in the first case by limit- 
ing the charging rate. Other corrective measures include the intro- 
duction of impedance in the discharge circuit to swing the voltage to 

FIG. 3. 

Schematic diagram of a condenser-discharge type of power supply for 
operating flashtubes. 

zero (or even slightly negative) or, in the extreme cases, the use of a 
switch tube in the discharge circuit. 

50 100 150 200 250 300 350 400 430 500 


FIG. 4. Electrical characteristics of a typical flashtube during the discharge 
cycle. The 26-/xf condenser was charged to 2000 v. 

Time-Light Characteristics. The duration of the flash of light 
and its variation in intensity with respect to time are intimately re- 
lated to the electrical discharge or pulse cycle. Fig. 4 shows typical 

May 1947 



curves of voltage and current variation during the cycle of a con- 
denser discharge through a flashtube with negligible impedance in 
the circuit; the electrical loading, per flash, is in the range used for 
still photography. Fig. 5 shows the variation of light output during 
that discharge cycle. Note the similarity of the curves for light out- 
put and current. The flash duration, now unnecessarily short for 
most motion picture applications, can be increased by adjustments 
in the characteristics of the discharge circuit. Such adjustments 
would, at the same time, substantially reduce the peak current. 
Studies of tube performance characteristics under such conditions 
are being made but are incomplete at this time. 




FIG. 5. 


Approximate time-light curve of a typical flashtube operated under 
the conditions shown in Fig. 4. 

Flash duration encountered with conventional condenser discharge 
systems may be calculated from the empirical formula 


Duration (in microseconds) = K 


where C is capacity in microfarads, V is voltage in kilovolts and K 
is a constant, depending upon what part of the total flash is con- 
sidered to constitute the useful duration. The value of K for flash 
durations to one-third peak is 20, and for flash durations to one-half 
peak, 14.5. 

Flashtube Efficiency and Photographic Effectiveness. Flash- 
tubes convert electrical energy into visible light with greater effi- 
ciency than do tungsten filaments. A comparison of efficiencies alone 



Vol 48, No. 5 

is always misleading when attempting to evaluate relative per- 
formance for photographic purposes because photographic materials 
evaluate differences in color quality of the light differently from the 
human eye. Tungsten filament sources used for photographic pur- 
poses have color temperatures of the order of 3200 K to 3400 K while 
flashtubes can have spectral energy distributions also closely approxi- 
mating those of black body radiators but at color temperatures 



4000 4200 4400 4600 4800 5000 5200 5400 5600 5800 6000 6200 6400 6600 6800 

FIG. 6. Spectral energy distribution of a typical xenon-filled flashtube, a 
CP filament lamp, and a CP lamp and Whiterlite filter. The approximate 
energies emitted are calculated for a time interval of l /w sec. 

ranging from about 7000 K to infinity. The increase in photo- 
graphic effectiveness of a source with increase in color temperature 
is already well established for a part of this range. 

In order to provide a more fundamental basis for the comparison 
of tungsten filament sources and flashtubes, values of radiant 
energy have been determined for each type of source for wave- 
lengths in the visible portion of the spectrum. To compare such 
data on a common basis it was, of course, necessary to assume some 
interval of time during which the radiation is effective. This time 
interval has been taken as 1 / 6 o of a second, the approximate maxi- 
mum exposure time for a frame of motion picture film. From an 
examination of these data, Fig. 6, it is apparent that, given a 

May 1947 FLASHTUBES 401 

flashtube capable of repetitive operation for relatively long intervals 
under the conditions described, it should prove more effective photo- 
graphically, per watt of input to the source, than the familiar CP 
tungsten filament lamps. Such a tube does not exist at the present 
time. The energy values used in the comparison were accordingly 
taken from data applying to single-flash operation. It is also appar- 
ent that such sources should produce less heat on the set. 

(a) (b) 

FIG. 7. Direct comparison of the sharpness of the recorded image when 
the exposure is made (a) with flashtube; (b) with continuous illumination 
during an exposure interval of Vso sec. 

From the foregoing discussion, it would appear that flashtubes 
merit serious consideration as a light source for motion picture 
photography. There are, however, many other factors which must 
also be considered. Some of them are already apparent to those who 
have been working on the problem; others can only be surmised at 
this stage of the investigation. In the following paragraphs an 
attempt is made to define the probable difficulties as well as they 
can be stated at this time. 



Vol 48, No 5 

Referring again to the data presented in Fig. 6, several factors 
enter into the final evaluation of photographic effectiveness in com- 
parison with other sources. For example, effectiveness is influenced 
by the relative actual exposure times employed. Also, since there 
seems to be a shift in contrast of the developed image, caused 

perhaps by short exposure time, 
and since this can be controlled 
within limits by development, 
the speed of emulsions may be 
subject to further variations, 
which are unpredictable at this 

Most of the data on flash- 
tube performance characteris- 
tics available today relate to 
single-flash operation in the 
field of still photography, where 
there is only moderate heating 
of the tube from one flash to 
the next. In this case, rela- 
tively high energy input levels 
per flash may be employed 
without detrimental effects, 
and minor variations in light 
output or in time to peak of 
flash are not of serious conse- 
quence. It is at these high 
energy input levels that 
greatest tube efficiency is 
realized, but the flashtube has 
not yet been developed which 
can be operated repetitively 
and reliably at these levels for intervals such as would be required 
for studio lighting. In the absence of such tubes, it is impossible to 
predict not only their cost and efficiency but also the over-all eco- 
nomics of a system employing them. 

Flicker Versus Flashing Rate. The problems of flicker with re- 
spect to the comfort of those working under intermittent illumina- 
tion will undoubtedly require special consideration. Most of the 
literature relating to this subject is limited to conditions where the 

FIG. 8. When two exposures occur 
in 1 /5o sec., multiple images are re- 
corded. This is the appearance of a 
portion of a single frame of motion 
picture film when the film is moving 
at a rate of 24 frames per sec and 
the tube is flashing at the rate of 
72 flashes per sec. Compare with Figs. 

May 1947 FLASHTUBES 403 

dark interval is equal to or less than the light interval and the inter- 
vals are uniformly spaced relative to time. With flashtubes, it may 
well be that the dark intervals will be as long as, or longer than, the 
light intervals and that an asymetric spacing of the intervals rela- 
tive to time would be desirable. It is known that the presence of 
some "continuous" illumination on which the intermittent illumina- 
tion is superimposed reduces the flicker effect, but even this part of 
the program has not been adequately explored for the special condi- 
tions which might prevail should such lighting be used in the motion 
picture studio. Whatever the solution to these problems may be, 
tests have demonstrated that the apparent level of illumination on 
the set is noticeably less than is required with continuous illumina- 

In any event, it appears improbable that a flashing rate of 24 per 
sec would ever be tolerable where live talent must be employed, even 
though there is a marked improvement in the sharpness of the pho- 
tographic image, Fig. 7. A flashing rate of 48 per sec might prove 
acceptable but, from the standpoint of over-all efficiency, would be 
undesirable because only half of the flashes would be utilized. A 
flashing rate of 72 per sec is quite comfortable to work under and is 
more efficient than 48 per sec because it should be practicable to 
utilize two out of every three flashes per frame of film. No foresee- 
able advantages exist for higher flashing rates. 

The presence of multiple flashes per frame, as in the case of 72 
flashes per sec, introduces another problem which must be con- 
sidered. With normal rates of object movement within the picture 
area, the resultant effect on motion picture film is very similar to 
that obtained with continuous illumination and conventional shut- 
ters providing exposure times of the order of Voo of a second. How- 
ever, when rapid rates of movement are encountered, two well-de- 
fined images of the rapidly moving object are recorded on the film, 
Fig. 8, with sufficient separation so that when projected it produces 
an effect different from that to which audiences are accustomed. 
The extent to which this is a detriment, and the extent to which it 
can be reduced by circuit design details previously mentioned re- 
mains to be determined. 

Effect on Sound Recording. It is still too soon to predict the ex- 
tent to which operation of flashtubes from either a condenser dis- 
charge of a pulsed source of electrical energy may effect sound re- 
cording. Quite obviously, intermittent operation of sources of this 

404 F. E. CARLSON Vol 48, No. 5 

type will create electrical transients which, if not properly shielded, 
could interfere. 

There is also some audible sound resulting from the flash, and it 
may be that means will have to be provided for its elimination. 

Artificial Cooling. As with all present sources of illumination, 
the operating limits for flashtubes will undoubtedly be dependent 
upon the presence or absence of some form of artificial cooling. Both 
air and liquid cooling are being investigated but insufficient in- 
formation is available to define the limits of operation for each con- 

Reliability. It would appear that, with properly designed power 
supplies, there would be negligible differences in exposure from one 
flash to the next. It must be recognized, however, that failure of a 
tube to flash due to any cause for even one cycle would have a 
detrimental effect on the final result. This means that the design of 
the entire system, including the source itself, must be such as to en- 
sure maximum reliability of performance. 

Power Supply. Because the energy must be delivered to the 
flashtube in pulses of relatively short duration, there may be special 
problems in power supply design to keep the size, weight, and cost 
at a minimum. 

Conclusions. Thus, it is apparent that flashtubes hold consider- 
able promise as a source of high photographic effectiveness adaptable 
to the exposure of either monochrome or color films. Because of its 
actinicity and the fact that the source is not continuously emitting 
radiation, there is a marked reduction in sensible heat in the picture 
area. Visually, too, the level of illumination to produce a given 
photographic result is noticeably less. 

On the other hand, it seems probable that new flashtubes, ex- 
tensive equipment, and new methods of silencing and of distributing 
power to flashtubes on sets would have to be developed in order to 
employ such sources for general motion picture photography. The 
practicability of such systems will, in the end, depend largely upon 
the costs involved, and these cannot be predicted accurately at this 


1 RYDER, L. L. : "Modernization Desires of a Major Studio", J. Soc. Mot. Pict. 
Eng., 47, 4 (Sept. 1946), p. 225. 

2 MURPHY, P. M., AND EDGERTON, H. E. : "Electrical Characteristics of Strobo- 
scopic Flash Lamps", /. Appl. Phys., 12, 12 (Dec. 1941), p. 848. 

May 1947 FLASHTUBES 405 

3 CARLSON, F. E., AND PRITCHARD, D. A. : "The Characteristics and Applica- 
tion of Flashtubes", Ilium. Eng. XLII, 2 (Feb. 1947). 


MR. DOVER: Would there be any future possibility that flashtubes could be 
made with the light source sufficiently small so that it could be focused by lenses? 

MR. CARLSON : Some experimental work has been done on such sources. 

DR. BACK: Several years ago we made exposures for some still pictures from 
the inside of the stomach, and we made some pictures with flashbulbs, and the 
exposure was too short. 

I think if you take the condenser and step it down to approximately 100 volts, 
it might work better. In this case the exposure time is increased. This might 
give a satisfactory result. 

MR. CARLSON : We have done experimental work over a relatively wide range 
of voltages. The highest efficiency of conversion of electrical energy into visible 
radiation occurs when the tube is operated at a relatively higher voltage although, 
as you point out, the flash duration is longer at the lower voltage. 

DR. KELLOGG: Sometime ago we tried to modulate mercury lamps and we 
found that there was too much energy stored in the arc stream. Can you tell 
us anything about the problem that you are up against in the storage energy in 
the arc stream of a flashtube? 

MR. CARLSON: There does not seem to be any problem in that respect, par- 
ticularly at the flashing rates discussed in this paper. I say that because such 
tubes have been used widely at higher flashing rates. It is very common, for 
example, to use tubes of similar design at flashing rates of the order of 1000 per 
sec or more. In fact, I have had reports of a flashing rate of 20,000 per sec. I 
do not think there is any modulation problem involved. 

DR. KELLOGG: Would not there be with mercury? 

MR. CARLSON: Yes. That is one reason why mercury is not a very satisfac- 
tory material to use for this type of source. These are filled with gases, usually 
xenon. Sometimes argon or krypton is used or mixtures of these gases. 

MR. RESS: How does the human eye stand up under this tremendous amount 
of lumens? 

MR. CARLSON: The eye seems to integrate the flash of that sort as the visual 
sensation is similar to that resulting from a relatively longer exposure time of 
much lower intensity. I have not heard of any instances where the high intensity 
of light had any detrimental effects. 

MR. LEE : Have you tried examining the effect of completely random pulsing 
the light source to eliminate these stroboscopic effects? You might have to go to 
higher rates, but I think you would get 50 per cent efficiency with a 180-deg shut- 

MR. CARLSON : Such tests have not been made, but it would appear that the 
result would also be random exposures per film frame. 

MR. REED: I noticed that when the baton was being twirled it seemed some- 
what jumpy when the exposures were made with flashtubes. Of course with uni- 

406 F. E. CARLSON 

form illumination it was quite blurred. Do you have any opinion which looks 
more nearly like the original? 

MR. CARLSON : I think the blurred image looks more natural. This, however, 
does not appear equally true when more normal rates of movement are photo- 

MR. REED: I would like to know if you have any indications what the life 
might be, operating at 48 cycles? 

MR. CARLSON : Complete data are not available. Tubes capable of operation 
at a few hundred watts seem to be showing lives of the order of 10 million flashes 




Aug. 1926: De Forest brought suit against Fox and Case, charging 
infringement of the Ries recording and reproducing patents, two of 
his patents covering the use of a gas discharge for sound recording, 
and a patent on the use of a light-sensitive cell with an audion am- 
plifier. (De Forest had purchased the Ries recording patent October 
15, 1925. He did not, however, actually acquire the Ries reproduc- 
ing patent until November 16, 1926, although it is believed he held 
an option on this and several Ries applications before this time.) 

De Forest did not press the suit for trial; it was finally allowed to 
lapse on the court calendar. 

Aug. 1926: At the time of the formation of the Fox-Case Corpora- 
tion, Sponable came to New York to take part in commercializing 
the Case system. With him came Mr. D. B. Eldred to assist in the 
business management of the company. Eldred, Case's brother-in- 
law, had joined the Case Laboratories in 1925. Courtland Smith was 
made general manager of the Fox-Case Corporation. "Movietone" 
was chosen as the name of the sound picture system. The industry 
is greatly indebted to Courtland Smith for his foresight and agres- 
siveness in hastening the commercialization of sound-on-film. He 
did more than anyone else to convince the "doubting Thomases" of 
the business that sound motion pictures were a reality and that the 
days of the silent film were numbered. He was instrumental in 
starting and developing Movietone News and later the Newsreel 

During this time plans were worked out for a sound picture pro- 
ducing unit. Sponable designed and built two studios at the Fox 
Annex at 460 West 54th Street. These were the first studios, except 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. (Parts 1 
and 2 published in the preceding issue of the JOURNAL, p. 275.) 
** Twentieth Century-Fox Film Corporation, New York, 


408 E. I. SPONABLE Vol 48, No. 5 

for experimental rooms, wholly designed for sound recording pur- 
poses. They were built to exclude all outside noise and with the best 
acoustic treatment known at the time. Dr. Paul Sabine, acoustic 
engineer of the Riverbank Laboratories at Geneva, Illinois, acted as 
a consultant in this work. 

Sept. 1926: Fox and Smith negotiated with the General Electric 
Company for rights to use vacuum-tube amplifiers commercially. 
The deal was nearly completed and General Electric equipment was 
brought from Schenectady to New York. At the final closing the 
parties did not agree, and General Electric withdrew their equip- 

It is interesting to note here that, if this arrangement had gone 
through, the whole setup of the future sound -business would have 
been changed. The Western Electric Company would probably 
have concentrated more and more on disk, and the Fox- General 
Electric group would have led in the development of sound-on-film. 

Oct. 25, 1926: The first test recording was made on the new Fox- 
Case Corporation stage. The next day a test recording was made of 
Harry Lauder. Typical of his Scotch character, he stopped singing 
during the middle of the recording of the song "Roam'in' in the 
Gloamin' " and said, "This is a test" to be sure it would not be 
used commercially. 

Nov. 4, 1926: Work was begun on making a number of one-reel 
short subjects with Racquel Meller, using regular motion picture 
production technique. 

Dec. 1926: Prior to this time, negotiations were carried on with 
the Western Electric Company to give Fox rights to use their am- 
plification patents and apparatus commercially. These culminated 
in an agreement or sublicense from the Vitaphone Corporation 
(see Part 5) in which Fox, among other things, agreed to pay a 
royalty of about 8 per cent of his gross business in the sound field. 

Jan. 21, 1927: The first public showing of Fox-Case "Movietone" 
subjects was given at the Sam Harris Theater in connection with the 
premiere of "What Price Glory". The sound features were not ad- 
vertised. The showing was made using a Case sound attachment 
with Western Electric main amplifiers. No stampede resulted, but 
neither was there an unfavorable audience reaction. 

Feb. 1927: Sponable developed a screen suitable for picture pro- 
jection and still transparent to sound without causing distortion. 
This enabled the use of loudspeakers directly behind the screen and 


was a great help in improving the illusion. This was immediately 
accepted by the industry. 

Feb.-Mar. 1927: The first field recording unit was assembled. 
With it, out-of-door recordings of a West Point review were made and 
the outfit was then sent to Italy for the purpose of making a record 
of the Pope and Mussolini. 

Mar. 11, 1927: The Roxy Theater, designed by S. L. Rothafel as 
the "last word" in motion picture palaces, opened in New York. 
Two weeks after its opening, Fox obtained control of the Roxy and 
laid plans to convert it for showing sound on film. 

Apr. 1927: Fox- Case made a new agreement with Electrical Re- 
search Products, Inc., superseding the Vitaphone sublicense. 
Electrical Research Products had been formed January 1, 1927 as a 
subsidiary of the American Telephone and Telegraph Company, for 
the purpose of handling the sound equipment business, instead of 
the Western Electric Company. 

May 1927: A showing of a West P.oint review as a sound feature 
was given at the Roxy Theater. 

May 6, 1927: Fox-Case Corporation's Field Outfit No. 1 recorded 
a speech by Mussolini and a number of Italian army subjects. This 
work was done by B. Miggins as cameraman and E. Kaw and D. F. 
Whiting as soundmen. 

May 25, 1927: A program was opened at the Harris Theater con- 
taining Movietone subjects. This included a silent version of 
"Seventh Heaven" and several sound shorts. 

June 12, 1927: Fox-Case recorded the Lindbergh welcome at 
Washington. Charles Gilson operated the camera, E. H. Hansen 
the sound equipment. The showing of this, together with his take- 
off, and the Mussolini pictures referred to above, created the second 
big sensation in the public showing of sound pictures (the "Jazz 
Singer" being the first). 

Sept. 1927: An all-sound program made up of the feature picture 
"Sunrise" with synchronized score, and the Mussolini pictures, 
opened at the Times Square Theater. This showing was made on a 
Western Electric sound-on-film installation. 

Oct. 28, 1927: The first "Movietone News" was shown at the 
Roxy Theater. The^ issue contained the following subjects: 

(a) Niagara Falls 
6) Romance of the Iron Horse 

410 E. I. SPONABLE Vol 48, No. .5 

(c) Army- Yale Football game at Yale bowl 

(d) Rodeo in New York 

Oct.-Nov. 1927: Sponable surveyed the Fox West Coast studios 
with a view to converting them for sound work, and drew up designs 
for the first unit. The building of these studios was held up by Fox, 
owing among other reasons to the estimated cost of $250,000 
being too high. 

Nov. 1927: Case suggested "noise reduction" in an affidavit dated 
November 28, 1927, quoted below: 

"It is of great advantage when photographing sound on film to 
have the ground noise level as low as possible between words or 
sounds when there is nothing on the film in the form of modulation 
to cover up the ground noise. A method of doing this has suggested 
itself to my mind as follows: If the recording light which itself is 
modulated or by another method is modulated mechanically is only 
eliminated while modulation is not going on in the circuit this would 
mean that when no modulation is present the light would be reduced 
to a minimum automatically or might even be put out entirely. 
This would mean that between modulation or between words or be- 
tween sounds the negative sound record would be unexposed or 
white upon development. This, on the positive, would be reversed 
or black thereby reducing any ground noise that there might be be- 
tween words or sounds. The method of accomplishing this could be 
the same as is at present used in the transoceanic telephony where it 
is essential that automatically only one sending station is in opera- 
tion. As soon as active modulation ceases in one direction and 
starts in the other direction the modulation passing in the circuit 
actuates a relay mechanism to instantly put into action this sending 
station. In other words in our simple modulation circuit any alter- 
nating or pulsating currents would actuate a mechanism to bring 
the recording light up to the brilliancy desired for the best operation 
of the system and while no modulation was passing, the light would 
automatically be reduced to the point where no record would appear 
on the film. 

"This is signed and witnessed at 9: 40 A.M., November 28, 1927 and I 
am now going to call up Dr. McKenzie at the Western Electric Com- 
pany and inform him of this idea so that it can be put into opera- 
tion, if they so desire, on their mechanical method of recording sound. 

s Theodore W. Case" 


During the last of 1927 and the first months of 1928, there was 
much activity in organizing and in developing sound equipment by 
the Fox- Case Corporation. Sound News outfits were put in the 
field at the rate of one or two a month. Various short subjects and 
productions wer^e made in the studios, largely to learn the best uses 
for sound and its limitations. Many silent pictures were synchro- 
nized. A test was made combining Technicolor with sound. A car- 
toon was made with sound effects. 

May 10, 1928: A non-exclusive agreement was made between 
ERPI and Fox- Case effective April 2, 1927. The royalty arrange- 
ment was changed from 8 per cent of the gross to $500 per negative 
reel for domestic release and a schedule for release in foreign coun- 
tries that added up to a second $500. 

May 1928: Equipment for three studio recording units was 
ordered by Fox- Case in anticipation of its coming West Coast studio 

During the spring of this year, Winfield Sheehan, in charge of pro- 
duction at the Fox West Coast Studios, who did not believe too 
strongly in sound in the beginning, came East and was anxious to 
arrange to get started on West Coast studio sound productions. He 
had taken over two news outfits that were originally assigned to 
West Coast news work. With these the Fox studio made a two-reel 
dialogue comedy, "The Family Picnic". 

June 18, 1928: This opened as part of the program with "The 
Air Circus" (synchronized sound) at the Globe Theater in New 

June 25, 1928: A Movietone field projector truck was used on 
Broadway to ballyhoo "The Red Dance" at its premiere. This out- 
of-door portable sound projection unit was a development of Fox- 
Case that has been used to some extent for political and commercial 

It now became Sheehan 's desire to get into sound as quickly as 
possible. This was accelerated by the fact that other producing 
companies were already starting. He brought various members 
of his producing staff East to work out a way of starting this work, 
and placed his Movietone development under the direction of his 
studio manager, Ben Jackson. They returned to Hollywood on 
July 12, 1928, taking practically the entire staff of engineers from 
Fox-Case. Operations were planned on a large scale. 

412 E. I. SPONABLE Vol 48, No. 5 

July 1928: Equipment for nine West Coast recording units was 

July 28, 1928: Several Movietone stages were started at Fox 
Hills, on a location which was previously used to corral Tom Mix's 
horses. These were erected under the direction of Mr. Sheehan, 
with C. H. Muldorfer as architect and H. K. Weeks as construction 
engineer. The completion of these sound studios and accessory 
buildings was accomplished with great speed and with much credit 
to the men responsible for the work. The whole plant took form in 
approximately ninety days. 

Aug. 1928: Equipment for twelve more West Coast recording 
units was ordered, making a total of twenty-four. 

Sept. 1928: Equipment for three European recording units was 
ordered. These orders from Fox, together with those of other com- 
panies coming into the field, swamped the facilities of the Western 
Electric Company and made deliveries of equipment very uncertain. 

This period was marked by a rapid growth of the technical staff of 
the Fox- Case Corporation. Many contributions were made by 
various individuals, particularly L. B. Hoffman, L. W. Davee, A. J. 
Sanial, H. E. Bragg, H. F. Jermain, Walter Hicks, R. F. Nicholson, 
and W. F. Jordan. Nineteen newsreel field outfits were operating. 
The crews of these units did much to overcome the initial difficulties 
of field operation. 

Sept. 1928: Fox Movietone City was dedicated. (This is the 
present Twentieth Century-Fox Studios at Beverly Hills, Calif.) 

Oct. 6, 1928: The Fox Movietone News release was increased 
from one to two issues per week. 

Dec. 1928: "In Old Arizona", the first out-of-door recorded 
feature picture, was shown at the Criterion Theater in Los Angeles. 
Quoting Franklin: "This film was photographed and recorded out- 
doors against a sweeping background of natural beauty, and in it 
sound recording achieved its highest artistic success up to that time. 
Filmed and recorded right in the vast open spaces, the scenes and 
human voice and all the accompanying sounds were reproduced with 
a clearness and naturalness that attracted wide attention. The 
Movietone process caught and reproduced with fidelity not only the 
voices of the actors, but actually the natural sounds of the outdoors : 
the whispering of the wind, the song of the birds. The picture was 
thus notable in combining the perfected technique of the silent film 
with the faithful recording of music, dialogue and sound." 

Subsequent Fox pictures that were well received and helped to 


advance the art of sound recording included the all-talking pictures 
"Through Different Eyes" and "Hearts in Dixie". 

Dec. 3, 1928: Fox Movietone News release was increased to three 
issues per week. 

During the year 1928, appreciable general progress was made in 
perfecting Movietone technique ; one point of note was the perfect- 
ing of the Aeo lights by Case, increasing their useful life and uni- 

Sponable organized a research department to which was assigned 
the problem of improving sound recording apparatus, particularly 
with a view to reducing its weight and improving its portability and 
ease of operation as well as the over-all problem of improving re- 
cording and reproducing equipment and techniques. Fifty-six field 
units were scheduled for assignment all over the world; three 
special Aviation Units were activated; to meet the need for such an 
increase in personnel, Bragg was sent to interview recent graduates 
at various technical institutions. Well over 100 engineers were now 
engaged in the sound recording field. 

Feb. 28, 1929: Fox acquired control of Loew's and MGM. 

Mar. 1929: Fox announced that all silent product would be dis- 
continued and only Movietone pictures would be made. 

July 15, 1929: The Fox Movietone News release schedule was in- 
creased to four issues per week. 

July 18, 1929: William Fox was injured in an automobile acci- 
dent; this may have seriously affected the following up of his in- 
volved negotiations. 

July 1929: British Movietone News, the first foreign sound news- 
reel producing company, was started. 

Aug. 1929: A merger of Fox Film, Fox Theaters, and Loew's was 

Sept. 20, 1929: Fox negotiated a deal acquiring Fox-Case stock 
from Case and exchanging Fox Theater stock to be redeemed Sep- 
tember 1, 1930. Fox then formed the Fox-Hearst Corporation, 
Hearst acquiring about 24 per cent of original Fox- Case stock with 
option to buy about 25 per cent more. 

Fox made a separate agreement with Case to have the latter run 
his laboratory until July 23, 1930. 

Sept. 1929: Fox and Hearst united their sound newsreels and 
agreed that each would release two per week. 

414 E. I. SPONABLE Vol 48, No. 5 

Sept. 17, 1929: An all-Grandeur show opened at the Gaiety 
Theater with Grandeur News and "Fox Movietone Follies". 

Sept. 28, 1929: Hearst Metrotone News released its first issue. 

Nov. 2, 1929: The Embassy Theater was opened with the first all- 
sound news program and called "The Newsreel Theater". 

1930: The crash of 1929 found the Fox structure in such a con- 
dition of over-expansion that it became necessary for Fox to sell out. 

Controlling interests in Fox Film and Fox Theaters were ac- 
quired by a group headed by Harley Clarke, who became president 
of the Fox companies. 

Sound-on-film by this time was well established as a commercial 
success and was displacing sound-on-disk as a release medium. The 
Western Electric light- valve method of sound-on-film recording was 
commercially perfected. As Fox Film was a licensee of ERPI, and as 
such paid the regular royalty rates, it decided to give up its own 
method of Aeo light recording and use in entirety the Western 
Electric system. 


Sept. 1922: The first showing of acoustic films was made at the 
Alhambra Theater, Berlin. These were made using the Tri-Ergon 
method with the sound recorded on a film about 42-mm wide and the 
sound placed outside the sprocket holes. (This system was worked 
out by three inventors Engl, Massole, and Vogt, who had formed a 
sound-film company called the Tri-Ergon A.G., of Zurich.) 

July 1926: F. A. Schroeder, who was the American representative 
of the German group, brought their system to the attention of 
Courtland Smith. 

Aug. 1926: John Joy went to Europe to investigate Tri-Ergon for 

Dec. 1926: At Joy's request Dr. Engl brought a complete unit of 
the German apparatus to New York for examination and tests. 
Records were made and shown under the direction of Dr. Engl; the 
results were judged to be fair, but not so good as Movietone. This 
was to some extent the result of the use of condenser loudspeakers in 
the German system. The equipment as a whole was typically Ger- 
man in design and offered few features that could be advantageously 
combined with the Movietone system. 

July 1927: Fox took over rights to the German system for North 


America and rejected a chance to acquire the world rights. This 
soon proved to be a mistake, since the patents became troublesome 
in foreign countries, and royalties were collected on them. 

Shortly thereafter, Joy and Shroeder went to Europe to get an ex- 
tension of scope to the Fox agreement to permit use throughout the 
world. Also during this time, UFA of Germany acquired a license 
under the German system. 

Feb. 1928: During the interval since July 1927, Tri-Ergon had 
tried to bring together all German companies interested in sound 
pictures including Siemens and Halske, AEG, and others. This was 
not entirely successful as Siemens and Halske and AEG wanted too 
much and Tri-Ergon would not agree to their stand. 

Aug. 1928: Tri-Ergon formed a German operating company 
backed by the Commerce and Private Bank and called Tonbild 
Syndicate A.G. (or Tobis) with rights in Germany, Switzerland, and 

Sept. 1928: Negotiations were carried on by Joy and Rogers for 
Fox with Tri-Ergon and Tobis to make a working arrangement to 
record and reproduce sound throughout the world under Tri-Ergon 
patents. No agreement was reached. 

Nov.-Dec. 1928: Schlesinger, of London and South Africa, who 
had purchased the de Forest Phonofilm Company, attempted nego- 
tiation with Tobis and Tri-Ergon for joining de Forest and Tri-Ergon 
on a world basis. This did not go through. 

Jan. 1929: Siemens and Halske and AEG combined interests in 
the sound picture field by organizing a company called Klangfilm. 

Klangfilm attempted to release a picture made by RCA in 
America in one of the UFA Theaters in Berlin. Tobis stopped this 
with an injunction on the grounds that the picture was recorded by 
double system, i. e., sound and picture separate, and recombined in 
a single positive. It was claimed this infringed Tri-Ergon patents. 
The result of the court's decision, sustained by the higher court, 
made Klangfilm make a working agreement with Tobis. 

During this time Fox interests kept up communication with 
representatives of Tobis and Tri-Ergon for the purpose of making a 
working arrangement through American Tri-Ergon to permit Fox to 
record and reproduce throughout the world under the German 
patents. No such arrangement was agreed upon. 

Apr. 1929: Attempts were being made at this time by various 
groups to join together the various Tri-Ergon interests and 

416 E. I. SPONABLE Vol 48, No. 5 

Klangfilm in opposition to Western Electric progress in foreign 
countries. Nothing resulted from this. 

June 1929: Kuckenmeister, a German phonograph manufacturer, 
through connections with Oyens and Sons, a Holland banking firm, 
became interested in organizing a holding company to unite various 
Tri-Ergon interests, not controlled by Fox, into one group. This 
was concluded in June 1929, and called "Acoustic Products Com- 
pany of Holland" . 

About this time Tri-Ergon started suits against Electrical Re- 
search Products, Inc., and during the summer obtained injunctions 
restraining the reproduction of all American pictures on ERPI 
apparatus in Germany. Some of the original decisions have since 
been sustained so that, except by special agreement with Tobis, 
American sound films were prevented from being released in Ger- 
many. Warner Brothers obtained a special license from Tobis and 
have released their films. 

May- Aug. 1929: Joy attempted to obtain a working agreement 
with Tobis to protect Newsreel recording and allow release of Fox 
products in Germany. No arrangement was concluded. 

Various conferences were held among representatives of ERPI, 
Tobis, Siemens, and AEG both in Europe and in America. No 
agreement was reached. 

Sept. 1929: Schlesinger concluded an arrangement with Kucken- 
meister in which his British company was allied with Tobis and 
Klangfilm. Advantages Fox could have had were now being ac- 
quired by others. 

Oct. 1929: Tobis brought suit against Movietone in Germany and 
Austria. All Fox Newsreel trucks were removed from these coun- 

During the last six months of 1929, both Tobis and Klangfilm 
moved forward, both in theater installations and in the production 
of sound pictures. They made an alliance with a French producing 
company, and arranged to begin sound work in France. 

June 1930: Will Hays headed a committee in Paris which met to 
deal with foreign sound problems and to attempt a settlement of 
German relations. This tangled situation was finally ironed out and 
a compact was arrived at on July 22 permitting the showing of 
American films abroad. 



1925-'26: Major development of the disk system of sound mo- 
tion pictures, later trade-named "Vitaphone", was carried on by a 
group in the Bell Telephone Laboratories headed by Dr. J. P. 
Maxfield. At about the same time, another group headed by Dr. 
Crandell and Dr. MacKenzie were working out a sound-on-film 
system using a "light valve" designed by Dr. Wente in the record- 

Apr. 20, 1926: Western Electric Company entered into a con- 
tract with Warner Brothers and W. J. Rich, a financier, giving 
them an exclusive license for recording and reproducing sound pic- 
tures under the Western Electric system. The Vitaphone Com- 
pany was formed. 

June 1926: The Vitaphone Company opened a recording studio 
at the Old Manhattan Opera House, 34th Street, New York. 

Aug. 6, 1926: Warner Brothers gave their first public perform- 
ance of Vitaphone at the Warner Theater, New York; showing a 
scored picture "Don Juan" and several shorts including a talk by 
Will Hays, and songs by Martinelli, Marian Talley, and others. 
This received favorable comment from some papers, enthusiastic 
comment from others, and grave doubts from the industry that 
talking pictures would ever be commercial. 

Dec. 1926: The Vitaphone corporation gave Fox a sublicense to 
use Western Electric equipment in the field of sound pictures. 

Dec. 31, 1926: Western Electric had equipped about twelve 
theaters with sound installations for Vitaphone. 

Jan. 1, 1927: Electrical Research Products, Inc. (ERPI) was 
formed as a subsidiary of Western Electric and AT&T to com- 
mercialize equipment for the sound motion picture field, the equip- 
ment business having been bought back from the Vitaphone Com- 
pany. The name Vitaphone was retained by Warner Brothers for 
their sound picture system. 

Spring 1927: Vitaphone recording was moved to Hollywood. 

Feb. 23, 1927: MGM, First National, Paramount, Universal, 
and PDC, termed "The Big Five", agreed to stand together for the 
purpose of determining the right sound system and used the facili- 
ties of the Hays organization for this investigation. 

Apr.-Aug. 1927: ERPI made their first light- valve installation 
in the Fox Movietone studio at 54th Street and 10th Avenue, New 
York. This was installed at ERPI's expense and operated 

418 E. I. SPONABLE Vol 48, No. 5 

experimentally by Bell Telephone Laboratory engineers. The ERPI 
film processing specifications were rigid and their technique of 
operation was not sufficiently advanced to impress the Fox group 
that the light-valve system offered any commercial improvement 
over the Case system then in use. 

Apr. 19, 1927: Warners secured 100 per cent ownership in Vita- 
phone by purchase of W. J. Rich's interests. 

Oct. 1927: Warners released "The Jazz Singer". This is spoken 
of as the turning point in the coming of sound, and served to con- 
vince the industry of its potentialities. 

Dec. 31, 1927: One hundred and fifty-seven theaters were 
equipped for sound, of which fifty-five included film units. The 
rest were disk only. 

Apr.-May 1928: ERPI contracts were signed by the "Big 
Five" group. This ensured the general use of talking pictures. 
The Warner contract was revised when ERPI took over the equip- 
ment business and a new Fox license was also signed about this 
time. Victor and First National announced the release of their 
product under the name of "Firnatone". The ERPI licenses 
granted during this period included the following companies: 
Paramount, United Artists, Metro-Goldwyn-Mayer, First Na- 
tional, Universal, Christie, Hal Roach, and Victor Talking Machine 

May-Dec. 1928: There was great activity in getting studios 
equipped for recording. Everyone wanted to start at once and 
equipment was at a premium, with deliveries most indefinite. 

At about this time, sound equipment and recordings were stand- 
ardized to a sufficient extent that apparatus made by either RCA 
or ERPI could satisfactorily play the product made with the other 
equipment. In the beginning, ERPI tried to restrict the use of its 
equipment to sound tracks made on the Western Electric system. 

July 1928: Paramount began recording in Hollywood on a tem- 
porary channel and first used sound in their picture "Warming 
Up", with Richard Dix. 

July-Sept. 1928: Their first all-talking picture was "Interfer- 
ence", directed by Roy Pomeroy. This was followed by "The Doc- 
tor's Secret"' and others. During this early work in a temporary 
studio, many of the scenes were made at night to avoid outside noises. 

Dec. 1928: Paramount began recording in its new sound studios 
on regular channels. 


Dec. 31, 1928: ERPI had 1046 theaters wired for sound, of which 
1032 were for sound-on-film. 

Jan. 1929: Warner Brothers became interested in the Pacent 
sound system and approved Pacent installations in April 1929. 
ERPI began suit against Pacent for patent infringements. 

Aug. 3, 1929: The first issue of Paramount Sound News was re- 

Dec. 31, 1929: The tremendous growth of the sound motion pic- 
ture business in a little over two years is evidenced by the fact that 
there were 77 ERPI recording channels in operation in the United 
States. ERPI also had equipped about 4000 theaters in this coun- 
try and some 1200 in Europe. Most of the theater installations 
were for both sound-on-film and sound-on-disk. 

Also at this time it became evident that there was a trend to 
favor sound-on-film over sound-on-disk for theater release purposes. 

Apr. 1930: Warner Brothers announced the purchase of an in- 
terest in the T. H. Nakken patents. These patents related to the 
use of a photoelectric cell and an amplifier. (Subsequently they 
were used as a basis for litigation.) 


1925: About this time, a small group of engineers at Schenectady, 
headed by C. A. Hoxie, experimented on recording sound on film 
photographically, using a special oscillograph as the recording unit 
and making records of the variable-area type. This sound-on-film 
system was called the "Pallophotophone". Also at this time, Hew- 
lett (a research engineer in the General Electric laboratory) was 
perfecting his induction-type loudspeakers, and Rice and Kellogg 
(also General Electric research men) were developing their electro- 
dynamic cone speakers. 

Feb. 1927: During the year 1926, probably stimulated by the 
work of Western Electric and others, the General Electric group 
combined their Pallophotophone with moving pictures and held a 
demonstration at the State Theater, Schenectady, in February 
1927, before a group of newspaper men and engineers. Their sys- 
tem of combined pictures and sound was called the "Kinegrapho- 
phone". The demonstration included speech and several musical 
numbers produced by amateur talent. Later this demonstration 
was given at the Rivoli Theater in New York. 

420 E. I. SPONABLE Vol 48, No. 5 

Mar. 1927: It was reported that five of the big producers were 
negotiating with General Electric to compete with Movietone and 

1926-'27: The research laboratory of the Westinghouse Electric 
and Manufacturing* Company, not to be outdone, carried on the de- 
velopment of a system of sound recording, using for its light modu- 
lator the Kerr cell based on the principle of the rotation of a beam of 
polarized light by electrostatic means. 

Toward the end of 1927, Paramount released its picture "Wings", 
with a sound score prepared by the General Electric group. This 
score was used in several different ways. At the Criterion Theater, 
New York, the airplane sounds were taken from disk recordings us- 
ing a multiple turntable device and synchronized by an operator 
back stage. The effects were reproduced in other theaters through 
the use of condenser-discharge devices as well as from a score re- 
corded on film. 

1928: The sound picture work of General Electric and Westing- 
house was combined into one system and handled by a new sub- 
sidiary of the Radio Corporation of America called RCA Photo- 
phone, Inc. The variable-density Kerr cell method of recording 
was dropped, and the variable-area system further perfected under 
the name of Photophone. RCA Photophone announced to the 
trade that it had perfected reproducing apparatus and would equip 

Oct. 1928: Shortly thereafter, RCA acquired the B. F. Keith and 
Orpheum chain of theaters and the FBO Producing Company. A 
subsidiary was formed called Radio-Keith-Orpheum. Through 
this producing organization, sound pictures made by Photophone' s 
methods were introduced to the public. The first efforts along 
these lines were limited to the presentation of musical accompani- 
ment; the first picture was "The Perfect Crime", which included 
some dialogue sequences. Important stage plays were acquired by 
the RKO producing organization, including the very successful 
"Rio Rita", which they produced as a sound picture. 

Feb. 9, 1929: RKO Productions, Inc., announced that 
they had selected "Radio Pictures" as the trade name for RKO 
Productions (which was the motion picture producing and dis- 
tributing unit of the Radio-Keith-Orpheum Corporation, sponsored 
by the General Electric Company, the Westinghouse Electric and 
Manufacturing Company, and National Broadcasting Company). 


An affiliation was subsequently effected with the Pathe Ex- 
change, Inc., which adopted the RCA Photophone System 
of recording in the production of sound motion pictures. The first 
Pathe production shown with a musical synchronization was 
"Captain Swagger" with Rod La Rocque; and this was followed by 
several others in rapid succession. The Pathe organization also 
released a sound newsreel recorded by the Photophone process. 

Jan. 1929: RCA closed a deal for the acquisition of the Victor 
Talking Machine Company. 

Mar. 1929: RCA, Tobis, and Klangfilm announced a working 

Dec. 31, 1929: RCA Photophone had equipped for sound about 
1200 theaters in the United States, and about 600 abroad. 

Dec. 1929: It was announced that RCA Photophone would 
shortly center all of its sound picture development work at Camden, 
N. J., combining the General Electric and Westinghouse groups who 
had previously operated independently. 


May 22, 1926: Thomas A. Edison declared no field exists for talk- 
ing pictures. 

Nov. 1926: A device called the "Remaphone" was brought out. 
It consisted of a Victor "Electrola" with two turntables connected 
by a shaft to the two projection machines in the booth. 

Feb. 1927: Synchrophone Corporation offered a new synchron- 
ization device for use in small theaters and provided music from 

Spring 1927: Vocafilm and Orchestraphone were made available 
for synchronizing pictures. The Orchestraphone was designed 
primarily for small theaters and initially tried in Chicago. 

July 1927: Vocafilm gave a showing using its sound picture sys- 
tem at the Longacre Theater, New York. 

Dec. 1927: Orchestraphone, marketed by the National Theater 
Supply Company, was shown at the Tivoli Theater, New York. 

Bristolphone was demonstrated before the Franklin Institute. 

Apr. 1928: Motion pictures were transmitted over telephone 
between Chicago and New York. 

Aug. 1928: M. A. Schlesinger bought control of the de Forest 
Phonofilm Company. He had previously held an option to pur- 


chase the company; this option had expired in 1927. General 
Talking Pictures was formed as the new operating company. 

Nov. 1928: Acoustic Products (Sonora) acquired manufacturing, 
distributing, and licensing rights to Bristolphone. . 

Dec. 1928: Cinetone, a sound device for home use, was offered by 

Jan. 1929: Pacent started installations approved by Warners. 

Sept. 1929: Powers Cinephone was placed on the market. 

Dec. 1929: At the end of this year, there were 234 different types 
of theater sound equipments in use; most of these, produced by the 
independents, were for sound-on-disk. The total number of theaters 
equipped for sound of all makes in the United States was 8741. Of 
these installations, ERPI and RCA had provided 4393. 

As has been indicated in the introduction, these notes have 
treated certain developments very fully and have made only the 
briefest mention of some others. This is not to be construed as a 
judgment of relative importance alone: rather, it also has been de- 
cided on the basis of what has previously been written on the sub- 
ject, and the author's more intimate knowledge of certain details. 
For example, the material on the Case work has, for the most part, 
never before been made public; and even this could not be reviewed 
in great detail in an article of this kind. It is hoped, however, that 
enough has been told to give the reader a concise picture of what 
took place during this rather brief development period. 

It has seemed appropriate to end this history in the early thirties, 
since at this time sound-on-film had completed the initial stages of 
its development, 1 and had justified its existence as a commercial 
achievement of the first order. 

[Ed. Note. Following Mr. Sponable's paper a film was exhibited 
demonstrating early sound-on-film, containing following subjects:] 

Subject Speed Date 

T. W. Case, close-up 75 March 1924 

Man with harmonica 75 March 1924 

T. W. Case (tuxedo) 80 April 1924 

Man playing harp 80 April 1924 

Man and duck 85 May 12, 1925 

T. W. Case, close-up 85 May 1925 

Chinese boy playing ukulele 85 June 1926 

Raquel Meller 90 November 1926 

Harold Murray 90 November 1926 

Sunrise (Scored silent) 90 June 1927 



Summary. The history of the sound motion picture industry is told from the 
point of view of the service organization. Particular emphasis is given to the part 
played by the service forces in the steady improvement of sound quality to its present 

The paper also discusses possible theater problems of the future which service will 
help solve. 

On August 6, 1926 the Sound Motion Picture was officially born. 
On that date the world premier of the Vitaphone was held at War- 
ners Theater, New York, the program consisting of "Don Juan" with 
a synchronized sound-on-disk score and a group of Vitaphone 
musical shorts together with a brief introductory talk by Will Hays, 
then czar of the motion picture industry. This was the official be- 
ginning of commercially successful sound and talking motion pic- 

The public and a great number of the producers were highly 
skeptical concerning the new sound pictures. Then on Oct. 6, 1927 
came Al Jolson in "The Jazz Singer" which, with two short dialogue 
sequences and several song numbers was a picture admirably suited 
to the taste of the entertainment-seeking public. This picture 
broke all existing box-office records wherever shown and convinced 
everyone that sound pictures were no longer a novelty but were here 
to stay. 

Revolution seized the entire motion picture industry. The 
equipment companies were besieged with thousands of exhibitors 
waving certified checks and begging for equipment. Many were 
glad to obtain a nine-month delivery promise. This sudden 

* Presented Nov. 13, 1946, at a meeting of the Atlantic Coast Section of the 
Society in New York. 

** Chief Engineer, Altec Service Corporation, New York. 


424 E. S. SEELEY Vol 48, No. 5 

demand for equipment placed a heavy strain on the principal 
manufacturers, Western Electric and RCA, despite their great 

But the greatest strain was placed on the new organizations whose 
role it was to install the equipment. These organizations mush- 
roomed. For some time all sources of the required type of personnel 
were scoured for men of suitable abilities and background at the 
rate of 75 to 100 per month for one of these organizations alone. 
Because of the urgent need for men in the field, the training period 
was all too brief for these men to master the technical mysteries of 
the sound systems, the mechanics of good installation practices, and 
the lore of the theater. 

Beginnings of Service (1927). To add to the burden, it immedi- 
ately became evident that the new equipment had a perverse tend- 
ency to break down when the house was packed with expectant 
patrons. It was soon apparent that in order to ensure continuous 
and satisfactory operation it would be necessary to establish an ad- 
ditional corps of trained specialists to service the sound equipment 
rather than leave it in the hands of those who were not familiar with 
this new complex electrical and mechanical apparatus. It was felt 
that the security of the future of sound pictures depended upon con- 
tinued satisfactory operation, and consequently in the Spring of 
1927 a service department was organized by ERPI in order to main- 
tain the equipment in operation without interference with the high- 
pressure installation schedule. The service department gradually 
emerged from its lowly beginnings and in 1937 became separated 
from ERPI to be known as Altec Service Corporation with the sole 
functions of maintaining and improving quality performance in 

Inevitable growing pains were experienced by the young operating 
organization. The new men, rushed into the field to handle some- 
times three installations at a time, often without help from their own 
supervisors, could not achieve completely what we consider the full 
standard of installation practice and improper conditions were 
sometimes left behind them. The new science of theater sound pro- 
jection was growing rapidly and the problem of applying the latest 
knowledge in the field developed. Furthermore, as the need for new 
men began to moderate somewhat it was considered necessary to 
recontact the field personnel to supply some of the training which it 
was not possible to give them when the pressure was most intense. 


To accomplish these several purposes a new group was formed 
who were known as Technical Inspectors. The Technical Inspectors, 
selected from the field on the basis of special technical ability, were 
given more advanced schooling in all parts of the sound systems. 
They then contacted the installation and service inspectors to fur- 
ther the training of the latter, and made detailed inspections of the 
new and established installations, perfected adjustments, reoriented 
horns, eliminated hums, made acoustic surveys and performed other 
valuable service functions to ensure proper functioning mechanically, 
electrically and acoustically according to improved standards. 

The technical inspection group continued in action until about 
1930, by which time the field personnel, now mostly service en- 
gineers, had been raised to the level of ability of the TI. The train- 
ing of the service inspector, however, has never abated. Special 
schools, new test methods, improved instrumentation and technical 
bulletins have been the means of maintaining steady growth in com- 
petence of the service he renders exhibitors. 

The day-by-day work of the service inspector is known to many 
of you ; his emergency service which quickly restores the health of a 
stricken system ; his periodical inspections and tests which keep the 
system healthy. These functions have long since been recognized as 
essential to guard the life blood of the theater. Service is a vital part 
of the motion picture industry. But this is not history and our in- 
terests are presently centered on the contributions of the service in- 
spector to the twenty-year development of sound quality. 

Projectionist Schools (1930 and 1931). It was, of course, per- 
fectly obvious that the success of the sound show was and will always 
be in the hands of the projectionist. But he had much to learn 
during the time that the installation was being made and the one-or 
two- week instruction period that followed installation. 

Projectionists wanted to learn more about the fundamentals of 
sound recording and reproduction. To meet this demand in 1930 
and 1931 one man uniquely qualified was assigned to the full-time 
job of conducting classes for the projectionists. These classes were 
held twice a day every day for about a month in space provided by 
the union locals in a considerable number of the larger cities where a 
sufficient number of projectionists could be brought together. The 
genuine desire of projectionists to master the new job of sound pro- 
jection was attested by the consistently good attendance at these 

426 E. S. SEELEY Vol 48, No. 5 

Calibrated Test Film and Transmission Test. It was inevitable 
that the inspectors scattered throughout the country tended more 
and more to become individualists. Several hundred pairs of ears 
did not interpret sound quality in the same manner. The TI group 
was an equalizing influence to some extent but with the termination 
of that organization the need was felt acutely for means of ensuring 
that each equipment was maintained to the same standard. The 
solution was the calibrated multifrequency test film and the trans- 
mission test. 

For several years technical inspectors and a few service inspectors 
had been using copies of a test film known as XX22. Readings 
were taken from this film, curves plotted, heads were scratched, but 
the inevitable question "So what?" remained unanswered. 
Means of interpreting the readings and standards of performance 
were required. 

Even at this early day a considerable variety of systems was found 
in booths. But most of them were made up from a much smaller 
variety of components. The method was therefore adopted of de- 
termining standards of performance or "normals", as they are 
called, for the various amplifiers, optical systems, etc., and thus 
equipping the inspector to determine the over- all or total normal for 
any particular system from such component normals. Thus was 
born the well-known Transmission Test. By this powerful tool an 
inspector could determine whether any sound system was perform- 
ing in the manner normal for that particular equipment. The test 
at once proved so effective in revealing substandard performance and 
leading to correction of long-standing troubles that it became clear 
that it must be placed in the hands of all inspectors in this country 
and in the organizations in foreign countries that enjoyed the bene- 
fits of service development here. 

Suitable compact meters were developed with the aid of the fore- 
most meter manufacturer. The provision of calibrated multifre- 
quency test films still presented a major problem. Repeated efforts 
failed to produce uniformly satisfactory prints from a negative 
satisfactory, that is for testing purposes. The recording experts sug- 
gested the "toe recording" method which obviates the printing 
process entirely, every foot of test film being recorded directly in the 
recording machine. R. O. Strock, then of Eastern Service Studios, 
worked out the practical details of large-scale production of test 
films by this process, and the result was an expensive but high- 


quality product that fully met our requirements. Through succeed- 
ing years, Mr. Strock recorded well over a million feet of test film for 

Each of the test films had to be individually calibrated against 
standards originally provided by the Bell Telephone Laboratories. 
Later, our own method of calibration known as the "inverse-speed" 
method was developed; and this method is still our standard means 
of calibration. 

With complete test equipment in the hands of all inspectors, the 
transmission test became a standard part of sound service. The test 
was somewhat enlarged and today this test includes measurements 
of frequency response, system gain, amplifier gain, required net gain 
for full house operation, system overload point, amplifier impedance, 
speaker impedance, and system noise. Limits of departure from 
normal for most of these tests are provided for most equipment. At 
regular intervals, each inspector applies all of these tests to each 
system which he services. His detailed report is studied by his 
supervisor to ensure that irregularities of importance are corrected. 
By this means, all theaters which receive this kind of service are as- 
sured that the correct standard of performance is maintained. 

Historically, the introduction of the Transmission Test on a 
universal basis eliminated much of the individualism in service and 
provided organization- wide standard performance. 

Noiseless Recording (1931). The problems faced by the pr,o- 
ducing organizations with the advent of sound and how the methods 
of production were revolutionized to solve them is an intriguing 
story that cannot be told here. Suffice it to say, however, that 
these problems were presently solved. Attention was then directed 
to means of improving the quality of recording. One of the defects 
of early film recording was the high level of noise present on the 
sound track. This film noise was not objectionable during loud 
passages, but during low-level intervals the noise was all too evident. 
It was found that darkening the track during the low-level sections 
greatly reduced background noise without interfering with the re- 
cording itself. This technique, still called "noise reduction", gave us 
what was publicized as "noiseless recording". The name was per- 
haps not an overstatement for 1930 to 1931 but recording engineers 
have striven valiantly in the succeeding fifteen years to produce true 
noiseless recording and are still hard at it. However, the improve- 
ment was dramatic. 

428 E. S. SEELEY Vol 48, No. 5 

Reduction of recorded noise, however, revealed the many noises 
produced by the reproducing system, noises which for the most part 
were not objectionable with the earlier recording. The first picture 
produced with noise reduction, "The Right to Love", with Ruth 
Chatterton, was widely publicized as having noiseless recording. 
The tremendous job fell upon the service forces to quiet reproducing 
systems during the first run period of this picture so that the pub- 
licized marvels of the new recording might be brought to the ears of 
the theater patrons. Late in 1930 and early in 1931 a "flying squad- 
ron" was formed from men brought in from all over the country and 
given a thorough training in a quickly improvised technique of mak- 
ing systems quiet eliminating clicks, microphonics, hisses, hums, 
etc. These men then scattered over the land and applied the new 
techniques to all equipments serviced by them. The expenditure for 
the training and the intensive field campaign was close to $100,000. 
Some of the stunts devised under pressure bordered on the fanciful, 
including hanging lead weights on vacuum tubes to reduce micro- 
phonics ; but they served their immediate purpose and the improve- 
ment in recording was well received. Soundly engineered im- 
provements, such as low microphonic tubes, soon replaced the hay- 
wire and the systems were left with the improvements in permanent 
and substantial form. 

We emphasize the part performed by the entire service organiza- 
tion in making this historical advancement in recording effective in 
theaters. It illustrates nicely the functioning of the entire team, the 
liaison with the producer organizations, the part played by the head- 
quarters engineering department and the broadcast action of the 
field forces. 

Wide-Range and High Fidelity (1934). Further developments in 
recording resulted in extending the recorded frequency range. 
Simultaneously, the equipment manufacturers developed systems 
which were capable of delivering the increased range to the listening 
public. This two-front development resulted in the introduction of 
wide-range and high-fidelity equipment and later the Mirrophonic 
systems, bringing with them new problems. Again the necessity 
arose of providing additional training of the service personnel in the 
intricacies of horn placement, draping, phasing, equalization, control 
of back-stage effects, and many other details required by this new 
horn system. Again, men were brought in from all districts and put 
through an intensive instruction course. In addition, trained 


specialists from headquarters traveled extensively throughout the 
field to assist in those cases where exceptional conditions were intro- 
duced by troublesome acoustical situations. 

Flutter Measurement (1936). Very important among the causes 
of poor quality in sound reproduction in the early sound systems was 
flutter. Flutter is a frequency modulation or warbling of the re- 
produced sound caused by nonuniform velocity of the film past the 
light beam. Flutter was present, often to serious extent, in all 
film drives. Xhe logical first step in correction of such a condition 
is to measure it. Designers of new equipment had laboratory- type 
flutter measuring systems but none of these was suitable for use by 
the service inspectors. The need for a small portable instrument 
became acute and in 1936 the TA-7421 Flutter Bridge was developed. 
This instrument was small, light in weight, simple to operate and 
economical of cost. A large number of these instruments are 
still in use in this country and many foreign countries.' Similar 
equipment was later adopted by other service organizations. 

Equalization of One-Way Systems. The Wide-Range, Mirro- 
phonic and high-fidelity systems introduced a new standard of sound 
quality in those theaters which were able to purchase this relatively 
expensive equipment. Thousands of theaters, however, had equip- 
ment of sturdy design which was still performing reliably and would 
evidently continue to perform reliably for some years, and a great 
many exhibitors did not consider themselves able to afford replacing 
their equipment at that time. The Altec service organization con- 
sidered it a duty to improve the quality of performance of such 
equipments in so far as possible within the limited financial means 
available to those exhibitors. 

The equipment installed in a large percentage of such theaters 
were the early Western Electric systems which had large horns 
equipped with 555W receivers. It was found that this loudspeaker 
equipment was deficient in reproducing the lowest frequencies and 
the highest frequencies, but that suitable equalization introduced in 
the amplifier circuits could in large measure compensate for these 
deficiencies. It remained to determine what equalization curve or 
curves would be required to do the best possible job. 

To facilitate the determination of the best equalizer character- 
istics in a considerable variety of theaters, a special equalizer of ex- 
treme versatility was developed which could be controlled from the 
listening position in an auditorium. This apparatus, described 

430 E. S. SEELEY Vol 48, No. 5 

before the Atlantic Coast Section of this Society in 1939, consisted 
of a portable amplifier which was set up in the booth and an equal- 
izer unit which was placed at any selected listening position in the 
auditorium with long cables interconnecting the two units. The 
equalizer system was arranged for insertion into any existing type of 
sound system and consisted of a number of mutually independent 
sections each controlling a portion of the spectrum and each ad- 
justable in calibrated steps over a considerable range of response 
changes. In practice, an engineer seated himself before the equalizer 
unit and, while a suitable diversity of program material was repro- 
duced, manipulated the various equalizer sections until the resulting 
quality was considered the best obtainable. The resulting response 
curve was then measured. Theaters were selected for the tests to 
provide a full variety of acoustical conditions and auditorium shape. 

These curves revealed that a relatively small degree of variation 
from a more or less universal curve would accommodate nearly all 
theaters but that a few required more significant departures from 
the average. The universal curve included a large rise at the 
lower end of the spectrum to re-enforce the base response and a 
larger rise to about 5000 cycles to provide good presence and a suit- 
able reproduction of sibilance. Without separate low-frequency 
speakers, the lowest base frequencies could not be reproduced by 
this horn equipment regardless of the amount of equalization em- 
ployed, but the cut-off of the horns was low enough for the equaliza- 
tion to provide a big improvement in the over-all base region. An 
inexpensive equalizer known as the AQ-1030 Equalizer was designed 
for insertion in most types of theater amplifiers. 

Improvement in the high-frequency response made more apparent 
than ever the flutter produced by the sound reproducer. Develop- 
ment of new sprockets provided a much better accommodation to 
the current normal film shrinkage than the sprockets originally in- 
cluded in the equipment, and reduction of cam action in the film 
drive sprocket made it possible to reduce the flutter in these older 
sound systems to values which were not evident to most casual 
listeners and were not distressing to the discriminating. 

A further shortcoming of the earlier systems lay in the somewhat 
deficient power capacity of the final amplifier. This deficiency was 
aggravated by the equalization. In co-operation with one of the 
largest tube manufacturers, a new tube was developed which in- 
creased the power capacity of a very large number of amplifiers from 


about I 1 / 2 watts to about 8 watts. The new tube had character- 
istics somewhat similar to one of the later Western Electric tubes but 
being designed for this particular application, it had a special type 
of base and a special filament voltage. One of the features of the de- 
sign was the much longer life and greater reliability than obtainable 
from commercial receiving tubes. These modifications were offered 
to those exhibitors who were not prepared to purchase new sound 
equipment, but care was exercised not to discourage exhibitors able 
to purchase new equipments from doing so. The program received 
the commendation of the Research Council of the Academy of 
Motion Pictures Arts and Sciences and it was highly successful in 
the field. The modifications were made in approximately 1500 
theaters over a short period of time, and it is believed that this con- 
stituted one of the major improvements in the quality of motion 
picture sound presentation when the total number of theaters af- 
fected is taken into account. 

Acoustic Measurements. A broad study was inaugurated by the 
Academy Research Council to determine the variation in acoustic- 
response characteristics in a large number of theaters. Nondirec- 
tional microphones, tripods, cables and related gear were supplied 
the field organization to operate in conjunction with the emergency 
amplifiers and output meters carried by all service inspectors. The 
signal source for measurements of this type was a warble film. Some 
misgivings were felt in connection with the make-up of warble films 
currently in use, and a theoretical study was made of this subject 
which was presented before this Society. The standard Academy 
warble film followed the principles set forth in this study. 

It was felt that a proper interpretation of acoustic response 
measurement required knowledge of the reverberation time charac- 
teristic of the auditorium in which the measurements were made. 
Existing reverberation measurement equipment was very cumber- 
some, expensive, slow, and time-consuming, and required very ex- 
pert analysis for evaluation of reverberation time. Our service 
organization, therefore, developed a compact, inexpensive, easily 
operated, and easily interpreted instrument for this measurement. 
For the instrument to be practicable for use by field forces in 
theaters on any significant scale, it required the foregoing character- 
istics; and in addition it had to be capable of yielding the desired 
data with a minimum expenditure of time during off-show hours. 
The resulting instrument as distributed in the field had these 

432 E. S. SEELEY Vol 48, No. 5 

qualities, and the degree to which it minimized the time consumed 
is best revealed by an actual demonstration. 

Postwar Speaker Systems (1945). New theater speaker sys- 
tems, of which we have installed many in the past twelve months, 
ushered in the postwar era in advancement of theater sound quality. 
For service, this major improvement in speakers brought a new 
challenge to raise the standards of performance of the rest of the 
system. Hums previously inaudible were now disturbing because of 
the extended low-frequency range of the new speakers. The im- 
proved presence necessitated closer attention to balance between 
machines, and the better over-all characteristic of the speakers 
made worthwhile the most careful selection of the best system re- 
sponse characteristic for the individual house. 

Maintenance of Quality. This discussion has traced the evolu- 
tion of quality in reproduction of sound motion pictures and the 
part service played in making these improvements effective in the 
theater. It has been an evolution largely by sudden changes. The 
recording industry has done its best to preserve improvements once 
introduced. It is the responsibility of the service organization to 
preserve the improvements that have been made in sound presenta- 
tion. If we may paraphrase a famous quotation, eternal vigilance is 
the cost of continued good sound quality. Whether the sound' 
equipment is of early vintage or one of the most recent, high stand- 
ards of quality will not be maintained unless intelligent periodic 
attention is given to the many sources of degradation of quality or 
introduction of foreign noises. Even such basic factors as con- 
tinuity of operation and keeping emergency situations to a mini- 
mum requires that all parts of the sound system be examined duti- 
fully and deteriorated parts replaced or readjusted as required. A 
characteristic of deterioration of sound quality caused by lack of 
proper service is the gradual manner in which deterioration occurs. 
Little by little, performance drops and the change may be so gradual 
as to pass unnoticed by the theater manager; yet the net effect be 
very serious. An effort will be made to demonstrate that gradual 
deterioration can creep in unnoticed because the change occurs in 
small amounts. 

Service During the War Years. World War II presented us with 
reduced manpower, priorities, curtailed production, gasoline ration- 
ing, and the many other regulations. While we do not think our 
wartime problems were any more severe than those of other 


organizations, we do know that in spite of these many handicaps 
we kept the theaters running. 

To many a well-meaning Government agency, the motion picture 
theater was just another unnecessary form of amusement in the 
same class with the juke box and pinball machine. Much can be 
said for the ingenuity of the individual service engineers during these 
early days of restrictions. All sorts of haywire arrangements were 
used to keep the shows running. 

As various Government agencies were formed and regulations 
issued, our representatives were sent to Washington to interview the 
headquarters of these agencies in order to correlate and interpret the 
regulations with regard to the theater industry. They were given a 
rather cool reception. 

Meanwhile, other Government bureaus were busy turning out 
propaganda films cautioning the public regarding the conservation of 
materials; dramatizing the activities of the FBI; exploiting the sale 
of war bonds and action pictures of our fighting forces. The conflict 
between the divergent views in Washington was finally resolved by 
President Roosevelt, who, in a public statement, recognized the 
necessity of keeping the motion piqture theaters operative to main- 
tain the morale of the public and to present to them the various 
propaganda films. 

This clearly necessitated servicing and maintaining the sound 
equipment. Altec representatives again made trips to headquarters 
in Washington and were now more cordially received. It was 
realized that they represented an established organization serving 
over 6000 theaters, more than one-third of the theaters in the coun- 
try, and knowing exactly their sound parts requirements. The ad- 
vantage of dealing with a single agency instead of 6000 individual 
theaters was apparent, and we became the focal point and the clear- 
ing house for the sound equipment needs of the theaters. 

As a result of our efforts, and those of representatives of certain 
major chains, a blanket priority classification AA2 was issued 
covering all repairs and replacement of equipment for theater sound 
systems. Even with such a high priority, a real problem remained 
of getting manufacturers and suppliers to furnish the equipment 
necessary to keep the theaters running. Our ability to purchase in 
volume, our distribution facilities, and close contact with all phases 
of the situation solved this problem economically and effectively. 
Then, too, the equipment in closed theaters and the spare parts 

434 E. S. SEELEY Vol 48, No. 5 

carried in each theater became a vast stock pile available through 
the service organization to all theaters. Basements and garages of 
service inspectors proved gold mines of now-prized parts which were 
once considered junk. Frequently, when we found the stock bin 
empty and desperate need arising, distress signals were broadcast to 
the inspectors and 250 men flushed the needed parts out of dusty 
corners, second-hand stores, and even pawn shops. 

Many unusual means were adopted for getting the last useful hour 
of operation out of each and every part of the sound systems. Test- 
ing and repair procedures were set up for vacuum tubes to conserve 
these parts so vital to the armed forces. Many electrical and 
mechanical parts which had formerly been discarded when they be- 
came defective were returned to our repair shop for rehabilitation. 
To conserve copper, we devised a unique method of repairing bel- 
lows assemblies, since each contains 14 ounces of strategic copper 
and there were several thousands used in theaters. While on the 
subject of copper, it can be mentioned that our field engineers served 
as the collection agency for copper drippings from arc-lamp carbons, 
and many pounds of this vital material were collected and turned 
over to salvage depots. 

One of our most difficult problems was that of getting sufficient 
gasoline for the field engineers to provide rapid transportation to 
theaters in case of emergency. The frequently changing regulations 
and their nonuniform interpretation by the local rationing boards 
made it difficult, and in some cases, impossible for these men to se- 
cure gasoline. Here, again, through correspondence, telephone calls, 
and trips to Washington, we finally succeeded in having a special 
regulation issued covering this situation. 

Space is not available for further details of the battle to keep the 
thousands of theaters operating through these troubled days, but we 
are proud to report that there was not a single instance of a theater 
serviced by us which shut down because of nonavailability of re- 
placement equipment. 

Future Service and Future Developments. Now, in closing, let 
us try to see what the crystal ball shows. The most reliable crystal 
ball in this case is a mirror which shows the future as an extension of 
the past. The pattern will not change radically, and step-by-step 
improvements will continue to reach the motion picture theater. 
These improvements will result in greater complexity in the tech- 
nical sense than those of the past and they will be brought speedily 


into the theater by the service organization. .The training of service 
inspectors will be as important as it has been in the past to provide 
them with the necessary knowledge to adapt the improvements to 
the individual theater and new tools and test equipment will be re- 
quired to ensure that all theaters are operating at their peak of per- 

What will be the nature of the new developments? A specific 
answer to this is not available to us, but we know that a great deal 
of competent engineering attention is being given to such things as 
control track, automatic volume control, stereophonic sight and 
sound, television, panoramic or wide angle sound origin, extended 
range, and new color film which will require modification of repro- 
ducing equipment. Means of standardizing auditorium loudness 
to ensure that each picture is reproduced at the volume intended by 
the recording director must be developed to ensure the greatest 
listening comfort and to bring out the" full quality recorded in the 
picture. Until the details of any of these developments crystallize, 
we cannot foretell today precisely the action that they will require 
on the part of our service organization. However, it is likely that 
improvements will come more or less abruptly and that large-scale 
efforts on our part will be required to ensure that no theater will be 
scooped by its competitor. History tells us that voluminous tech- 
nical information must be prepared and distributed to the field men 
and that new standards of performance will be established for uni- 
form maintenance to preserve the advancement. 

The following steps will illustrate the manner in which a complete 
service organization proceeds as new developments are brought to the 
point where they are ready for the theater : 

(a) Close liaison with and participation in the activities in 

Hollywood and those of the equipment manufacturers al- 
low us to anticipate and prepare for the development. 

(&) A competent headquarters engineering staff appraises the 
approaching development in relation to the individual prob- 
lems presented by all the numerous specific types of sound 
reproducing equipment, and prepares the required technical 
information for the field, adaptation details where required, 
and the necessary tools and test methods. 

(c) The field organization copes with the actual application of 
the innovation in each particular theater. 

436 E. S. SEELEY 

(d) Following the exciting period during which the innovation 
is introduced, the service inspectors guard the equipment 
performance to ensure that the new standard of quality is 
maintained and all new components are watched on a 
nation-wide basis to correct at the earliest possible time 
frailities which may develop in the first few cases during 

It is obvious that the individual or small local service group can- 
not possibly render the complete and comprehensive service that is 
required by the exhibitor. Contact with the producer and equip- 
ment suppliers must be completely lacking ; a competent and informed 
engineering department cannot provide the essential firm foundation, 
for their activities, or provide them with up-to-the-minute informa- 
tion, instructions, tools, and techniques ; equipment troubles must be 
experienced in a large percentage of the theaters involved before 
remedial measures can be developed; service improvements in 
reliability of apparatus and quality standards will generally be lacking 

With the protection accorded him by our complete organization, 
the exhibitor may welcome approaching evolution with confidence 
and without apprehension. Thousands of exhibitors, the backbone 
of the industry, will continue to attest to the necessity to them of 
such a complete organization. 


Ed. Note. By action of the Board of Governors, Oct. 4, 1931, an Honor Roll 
was established to perpetuate the names of distinguished pioneers who are now de- 
ceased. It is published monthly on the inside back cover of the JOURNAL of the 
Society and now contains seventeen names. In 1946 three outstanding early workers 
in motion picture sound were approved by the general membership to be added to the 
Honor Roll, and the high lights of their activities in this field are published below. 


Theodore Willard Case, American scientist, was born in Auburn, 
N. Y., Dec. 12, 1888, and died May 13, 1944. Son of Willard 
Erastus Case and of Eva Fidelia (Caldwell), Mr. Case received his 
preparatory education at Cloyne House School, Newport, R. I., 
and at St. Paul's School, Concord, N. H. He then entered Yale 
University, where he was graduated with the degree of B. A. in 1912. 
He received an honorary Sc.M. from George Washington University 
and was a member of the American Association for the Advance- 
ment of Science, the American Electrochemical Society, American 
Museum of Natural History, American Physical Society, New York 
Electrical Society, Optical Society of America, and the Royal So- 
ciety of Arts, London, England. 

Mr. Case was married at Auburn, New York, Nov. 26, 1918, to 
Alice Gertrude Eldred, daughter of George Field Eldred, a merchant 
of that city. They had four children. 

Mr. Case began experimenting on sound recording while a student 
at Yale. In 1914 he started a research laboratory at Auburn, N. Y., 
and began intensive studies to find the substances sensitive to light. 

Probably the most important outcome of this early research was 
the Thalofide Cell (a light-sensitive change of resistance material 
similar to selenium but a form of thallium sulfide particularly sensi- 
tive to infrared radiation). This was used by the Navy as the re- 
ceiving element in an infrared signal and communications system 
developed for them during World War I. During this war the Case 
Laboratory, working in conjunction with the Naval Experimental 
vStation at New London, Conn., was entirely devoted to war work 


438 T. W. CASE Vol 48, No. 5 

and carried on extensive research in the transmission and amplifica- 
tion of speech and signals in connection with its infrared system. 

After the war, Mr. Case discovered the barium photoelectric cell 
and began its development. In its final form it was used in a re- 
corder of daylight and sunlight. 

In 1922 he constructed a crude sound camera and made a sound 
picture using a modulated oxy acetylene flame. This was the same 
manometric flame that had previously been developed for use in 
infrared telephony. 

Shortly thereafter Case found that the gas discharge in an argon 
filled oxide-coated vacuum tube, formerly used in his infrared signal 
system, could be easily modulated at a low voltage and that it 
seemed suitable for sound recording purposes. This led to the de- 
velopment of the Aeo light and was a big step in making this system 
of sound recording practical. The Aeo light operated on direct cur- 
rent at 200 to 400 v and was highly actinic. 

From this point on, the Movietone system of sound recording was 
developed and perfected step by step under his sponsorship. In- 
cluded in this development was the Physical Slit using a cover-glass 
of quartz with the portion over the recording aperture less than 
0.001 in. thick. This solved the problem of recording with a flashing 
lamp without having the slit fill with dust and dirt and was one of 
the fundamental steps in making the Movietone system practical. 

A projection attachment was designed to fit below the standard 
Simplex head. The first model is still in existence, and is practically 
identical in design with some of the latest type theater units. Every 
step in recording and reproducing sound was carefully studied and 
developed at the Case Laboratories to the end that in 1926 the 
Movietone system of sound recording was sold to William Fox, sub- 
stantially complete in every detail. 

A glimpse of Mr. Case's activities may be gained through a list of 
some of his scientific papers, published articles and patents as fol- 
lows : 

"Preliminary Notes on a New Way of Converting Light into Electrical Energy", 
read before the New York Electrical Society, June 14, 1916. 

"Notes on the Change of Resistance of Certain Substances in Light", Physical 
Review, April 1917. 

"A Cuprous Oxide Photo-Chemical Cell", presented at the meeting of the 
American Electrochemical Society, May 2, 1917. 

"Thalofide Cell, a New Photo-electric Substance", Physical Review, April 

May 1947 



"A Photo-Electric Effect in Audion Bulbs of the Oxide-Coated Filament Type", 
presented at a meeting of the American Electrochemical Society, Apr. 21, 1921. 

"The Effect of a Photo-Electric Material on the Thermo-Electric Current in 
High Vacuum Audion Bulbs", Journal of the Optical Society, August 1922. 

"A Photo-Electric Effect in Audion Bulbs of the Oxide Coated Filament Type", 
presented at a meeting of the American Electrochemical Society, Apr. 21, 1921. 

"The Effect of a Photo-Electric Material on the Thermo-Electric Current in 
High Vacuum Audion Bulbs", Journal of the Optical Society, August 1922. 

"Infra-Red Telegraphy and Telephony", Journal of the Optical Society, June 

"New Advances Made in Talking Movies", Yale Scientific Magazine, May 1927. 

"Thalofide Cell", Bulletin, No. 4, 1921, Case Research Laboratory, Inc. 

"Barium High Vacuum Photo-Electric Cell", Bulletin, No. 6, Mar. 6, 1928. 

(The last two papers were also read before the Physical and Optical Societies 
Joint Discussion in England, June 4, 1930.) 




















Variable Resistance 
Variable Resistance 
Variable Resistance 
Variable Resistance 
New Compound Showing Variable Resistance Under 

the Influence of Light 
Light Reactive Resistance and Method of Forming 


Electrical Device 
Resistance Element 
Signaling System 

Process of Producing Photo-Electric Cells 
Photo-Electric Cell 
Photo-Electric Cell 
Radiant Energy Signaling System 
Wireless Receiver 

Radiant Energy (Detecting and Trans. Device) 
Electrical Device 
Signaling System 
Apparatus for Recording Light 
Photo-Electric Cells 
Apparatus for Determining and Measuring X-Ray 

Active Grid* 

Methods of Manufacturing Mirrors 
Method and Apparatus for Translating Sound Wave 


Transparent Covering for Slots 
Reproducing Apparatus 


Mar. 25, 1919 
Mar. 25, 1919 
Apr. 22, 1919 
July 8, 1919 

Sept. 16, 1919 


Sept. 16, 1919 
Oct. 7, 1919 

8. 1920 

1. 1921 
3, 1921 
3, 1921 
3, 1921 

May 24, 1921 
May 24, 1921 
Sept. 13, 1921 
Feb. 7, 1922 
Apr. 11,1922 
May 15, 1923 
Nov. 24, 1925 

Oct. 20,1925 
May 18, 1926 
June 8,1926 
June 8,1926 

June 8,1926 
July 27,1926 
Nov. 2,1926 
Nov. 2,1926 



Vol 48, No. 5 

1.605.528 Slot Unit Nov. 2, 1926 

1.605.529 Slot Unit Nov. 2, 1926 

1.605.530 Method of Producing Slot Units Nov. 2, 1926 

1.605.531 Slot Unit Nov. 2, 1926 
1,624,314 Electrical Apparatus Apr. 12, 1927 
1,625,409 Light Reactive Apparatus Apr. 19, 1927 
1,628,822 Photo-Electric Device May 17, 1927 
1,631,085 Electrical Apparatus May 31, 1927 

1.638.392 Talking Moving Picture Machine Aug. 9, 1927 

1.638.393 Talking Picture Machine Aug. 9,J927 
1,638,472 Translating Device Aug. 9, 1927 

1.647.502 Electrical Apparatus Nov. 1,1927 

1.647.503 Reproducing Amplifier Nov. 1, 1927 

1.647.504 Sound Producing Apparatus Nov. 1, 1927 

16,910 Talking Picture Machine Mar. 20, 1928 
1,718,999 Method and Apparatus for Translating or Trans- 
mitting Sound Waves July 2, 1929 
1,724,872 Photo-Active Thermo-Elec. Devices Aug. 13, 1929 
1,747,225 Apparatus for Producing Photographic Records of 
Light Variations Corresponding to Sound Varia- 
tions Feb. 18, 1930 
1,747,287 Source of Light Feb. 18, 1930 
1,749,412 Talking Picture Apparatus Mar. 4, 1930 
1,753,022 Camera Apr. 1,1930 
1,759,434 Apparatus for Producing Photographic Records May 20, 1930 
1,774,253 Reproducing Slit Aug. 26, 1930 
1,781,945 Talking Picture Machine . Nov. 18, 1930 
1,785,070 Inductive Light Source Dec. 16,1930 
1,788,355 Source of Light Jan. 6,1931 
1,790,898 Method and Apparatus for Transmitting Motion Pic- 
tures Feb. 3, 193 1' 
1,803,278 High Frequency Control of a Kerr Cell Apr. 28, 1931 
1,816,825 Aeo Light Aug. 4,1931 
1,822,865 Method and Apparatus for Producing Photographic 

Records Sept. 8,1931 

1,861,738 Cell Capable of Showing the Kerr Effect June 7, 1932 

1,865,055 Photographic Apparatus June 28, 1932 

1,872,404 Camera Shutter Aug. 16,1932 

1,872,675 Cell and Method of Making the Same Aug. 23, 1932 

1,896,682 Method of Eliminating Noises in Spliced Film Feb. 7, 1933 
Similar patents in leading foreign countries were also granted. 


In 1925 the talking picture was presented to the motion picture 
industry as a practical reality. The technological development 


which made this possible was due largely to the personal leadership 
of one man Edward Beech Craft. 

Up to that time there had been numerous attempts to make 
pictures talk, but none had produced more than a scientific novelty. 
None had displayed the quality of sound reproduction, the volume 
of sound, in short, the realism needed for commercial success. 

Mr. Craft had become interested in this problem several years 
earlier. He had been directing, in the laboratories of the Bell Sys- 
tem, a program of development which had produced the public 
address system, radio broadcasting, and the electrical recording 
which was to bring about the revival of the phonograph industry. 
These were products of research in telephone communication, and 
one of Craft's outstanding qualities was the urge, and with it the 
ability, to guide the products of research as rapidly as possible into 
practical channels. 

The development of sound pictures went hand-in-hand with that: 
of electrical phonograph recording. As a matter of fact, before the 
phonograph industry 'had become interested, Craft gave the first 
showing of a motion picture with the new sound system outside the 
laboratories. This was when he demonstrated, at Woolsey Hall, 
New Haven, on Oct. 27, 1922, a film describing the three-element 
vacuum tube, the action being explained by a lecture delivered from 
electrically recorded disks. 

In spite of the fact that during the time when these developments 
were going on he was, as chief engineer of the Western Electric 
Company, responsible for the company's entire program of research 
and development, he found time to give his close personal attention 
to the work, suggesting many of the steps and making many of the 
decisions. An indication of the amount of research carried on in the 
laboratories under Craft's direction in the field of sound pictures is 
the fact that, up to the time of the release of "Don Juan" in the 
Warner Theater on Aug. 6, 1926, several hundred patent applica- 
tions had already been filed for the laboratory engineers covering 
disk and film recording and reproducing methods, loudspeaking 
apparatus, microphones, synchronizing, and regulating systems, 
light valves, and photoelectric cells. 

Had it not been for Craft's will power and faith the application of 
these developments to talking pictures might have been postponed 
for a long time. Fortunately, however, he possessed the imagina- 
tion and enthusiasm to follow through to a successful conclusion, 

442 T. W. CASE Vol 48, No. 5 

and he had in addition a personal influence that inspired those who 
worked with him to carry on even when the going was far from 

At one stage, in order to carry on the work on electrical recording 
when circumstances made it difficult to do so in what he considered 
an adequate manner in the Bell System Laboratories, Craft brought 
about the formation of the Phonic Laboratories, a company organ- 
ized by a group of those people, few at that time, who believed in 
the commercial future of the development. Some of the experi- 
mental work which later resulted in the electrical recording system 
adopted by the phonograph industry was done in the Phonic 
Laboratories. This system formed the basis of the sound system 
used for talking pictures. It was due to Craft's untiring zeal that 
efforts of this sort were made and that sound pictures were demon- 
strated to the industry in 1925 in a sufficiently advanced state to 
.capture the imagination of the Warner brothers and result in the 
formation by them of the Vitaphone Corporation in 1926. 

The sketch of E. B. Craft's life which follows speaks eloquently of 
the character and ability which carried him so directly to the goal 
that he set for himself and enabled him to push to a triumphant con- 
clusion what proved to be his last job. 

He was born in Cortland, Ohio, on Sept. 12, 1881. He received 
common and high school education in the nearby town of Warren, 
where he started to work. From 1900 to 1902 he was superintendent 
of the Warren Electrical and Specialty Company, which position he 
gave up to join the Western Electric Company in Chicago because 
he felt that it was doing the kind of work he wanted. 

He was soon put in charge of a group doing development work, 
and his first patent was for an indicating device for telephone fuses 
which has since remained constantly in use. With the consolidation 
of the development and research work in the Bell System in 1907, 
Craft and a nucleus of the force which he had formed in Chicago 
moved to New York City, where he became development engineer 
and later, in 1918, assistant chief engineer of the Western Electric 

During the first world war he served as a captain and later as a 
major in the Signal Corps, U. S. Army, and as a technical advisor, 
U. S. Navy in England. His interest in radio and other applications 
of research, and his insight into research problems, not only made 
his advice of value to the armed forces but later resulted in his being 


put in charge of all Western Electric's research as well as develop- 
ment activities in 1922 as chief engineer. With the incorporation of 
Bell Telephone Laboratories at the end of 1924 he became its execu- 
tive vice-president, and soon after a member of the Board of Direc- 

Among his publications were a joint paper with E. H. Colpitts 
presented before the American Institute of Electrical- Engineers in 
1919, which described the early work in radio telephony in which he 
took part; a joint paper with L. F. Morehouse before the AIEE on 
dial switching, to which Craft made many individual contributions; 
and a paper on Airways Communications Service published in the 
Bell System Technical Journal in 1928. 

In addition to his active duties in the Bell System, he was vice- 
chairman of the Division of Engineering and Industrial Research of 
the National Research Council, chairman of the Board of Engineer- 
ing Societies Library, a Fellow of the AIEE, and one of its managers 
from 1920 to 1924, a Fellow of The Institute of Radio Engineers, a 
member of the Council of the American Institute of Weights and 
Measures, a member of the Society of Automotive Engineers, and 
representative of the Bell System in the Aeronautical Chamber of 

During the middle of 1928 an ailment of some years standing be- 
came acute, and from October of that year he was absent on sick 
leave. His health grew worse and death occurred on the twentieth 
of August 1929. 

On receiving an honorary degree of Doctor of Engineering from 
Worcester Polytechnic Institute in 1926 he was cited as: 

"Engineer, Inventor, and Organizer of Research; whose inventions take part 
daily in each of more than fifty million telephone conversations; whose genius, 
. initial conception of panel systems for machine switching, and continued super- 
vision of its development have contributed largely to the present system of 
telephony; whose technical experience devoted to the service of his country 
during the World War hastened advances in radio-communication with air- 
craft; whose organizing ability continuously applied for a quarter of a century 
to engineering development and industrial research has increased the social 
and economic significance of research." 


"Come on, Ma, listen to this." These six words spoken in the 
Warner Bros, picture, "The Jazz Singer", touched off public ac- 
ceptance of talking pictures that was to revolutionize the motion 

444 T. W. CASE Vol 48, No. 5 

picture industry overnight. For Sam Warner, this was the climax to 
his efforts and the vindication of his faith in the future of talking 
pictures. Although he was never to share in the triumph which he 
had done so much to create, he will be remembered as the one man 
in the motion picture industry who had confidence and belief in the 
future of sound motion pictures. 

To appreciate fully the vision and courage of Sam Warner, it is 
important to recognize that he set out to introduce talking pictures 
at the very moment when the art of the silent film was at its highest. 
Talking pictures were virtually experimental, while the industy was 
experiencing its greatest success and popularity, as it released bigger 
and more spectacular features to the public. 

While other leaders in the industry were skeptical, or even hostile, 
Sam W T arner was enthusiastic. He took the risks necessary to make 
talking pictures a reality; he contributed technical development by 
bridging the gap between laboratory performance and commercial 
and artistic practicability; he contributed showmanship by recog- 
nizing that the .way to demonstrate the power of the talking picture 
was to film performances of the finest musical artists in the world. 

Lee deForest, writing in the JOURNAL in January 1941, said : ' 'Un- 
questionably, it was the absolutely unique prescience and courage of 
Sam Warner, and later his brothers, which finally resulted in arous- 
ing the motion picture industry to the belated realization that here 
at last science and invention had created a new instrumentality." 

Sam Warner was born Aug. 10, 1888, in Youngstown, Ohio, and 
died Oct. 5, 1927. He had an early introduction to show business 
by carrying water backstage for the Youngstown Grand Opera 
House when he was ten years old. While working at the Opera 
House, he met an electrician who became a good friend of Sam's, and 
taught Sam the art of taking a projector apart and putting it to r 
gether again. The machine, in those days, was operated by hand 
and used a calcium light. 

Once he learned how to run a projector, he got a job as an ex- 
perienced operator to run Hales Tours, at White City Park in 
Chicago. In the tonneau of an old-fashioned motor car, he ran 
pictures of "A Trip Through Yellowstone Park". The admission 
price was ten cents, and the show, which could accommodate fifteen 
people, ran for five or six minutes. This so intrigued Sam that he 
wanted a machine of his own. So he pawned his watch and bor- 
rowed enough money from his father to raise $600 to buy a 


projection machine and a set of slides from a woman who ran a board- 
ing house for actors. Her son wanted to get rid of the outfit anyway 
and return to vaudeville; so he was willing to part with it. 

That night, Sam borrowed the horse and wagon used by his 
father to deliver meat and groceries from the family market, 
loaded in the projector, and brought it to the house. There his first 
show was run for the family and neighbors on the lawn ; and every- 
one was afraid that the gas lamp on the old Enterprise machine 
might explode and set the house on fire. Eventually, through easy 
stages, he got the people to see the show in the house. 

Soon he rented a store in Niles, Ohio, and gave shows for the 
public, charging an admission of five cents. Sam ran the projector, 
his sister, Rose, took the tickets and then played the piano, and his 
brother, Jack, led the singing to the slides. Soon another brother, 
Abe, came on from Pittsburgh to manage the business and then 
Brother Harry joined the venture at Newcastle, Pa., to handle the 
finances. Pictures were rented from the Pittsburgh Calcium and 
Light Company, but competition was growing, so they began to buy 
films for themselves and also to rent to others. They called them- 
selves the Duquesne Amusement and Supply Company. In 1912, 
they went to New York and began to make pictures for themselves 
at the old Vitagraph Studio in Brooklyn. A few years later they 
acquired space for a studio in Hollywood and made most of their 
features there, keeping the Brooklyn Studio for short subjects. 

In 1925, Sam saw a demonstration of sound pictures at the Bell 
Telephone Laboratories, which was arranged for him by Major 
Nathan Levinson, of the Western Electric Company, who had 
helped him get a radio transmitter for the company. Sam was en- 
thuiastic and began a campaign to sell the idea of sound pictures to 
his brothers. His brother Harry thought it might be well to use the 
sound as a musical accompaniment for pictures. But he knew only 
too well the magnitude and risks of the business enterprise they were 
undertaking. Sam understood fully the technical difficulties which 
had to be solved; but he had faith that they could be overcome. 
He was the most mechanically minded of the brothers and set out 
to do all he could to make a really commercial sound picture. 

With the help of the Western Electric engineers, he made a series 
of experiments with sound pictures during the autumn and winter 
of 1925-'26. He had a crew of cameramen, soundmen, actors, 
writers, musicians, and studio technicians make simple sound 

446 T. W. CASE Vol 48, No. 5 

sequences at the Vitagraph Studio while his brothers continued 
to make silent pictures in Hollywood. He had Herman Heller, 
who conducted the orchestra at one of the Warner Theaters, bring 
the orchestra, a tenor and a pianist to the studio for test recordings. 
He worked day and night; and slept, ate, and lived sound pictures. 

In April 1926, the Vitaphone Corporation was formed to develop 
and market talking pictures and talking picture apparatus. Sam 
was made vice-president of the company. 

His experiments were interfering with the company's normal 
business of making silent films, and it soon became necessary to find 
a place other than the Vitagraph Studio to carry on further tests. 
The Manhattan Opera House in New York City was leased for this 
purpose, and sound recording apparatus was installed in the audi- 
torium and on the stage. 

Recordings were made with a number of great artists for Vitaphone 
Shorts, and the New York Philharmonic Orchestra was recorded 
with an especially prepared score for the feature, "Don Juan". 
With all its success, the heads of all other film companies, except 
one, decided against the production or exhibition of sound pictures. 
They were still not convinced that sound had come to stay. 

Sam Warner started shifting his crew to the Hollywood Studios, 
where two new stages were built especially for sound pictures. He 
had learned a lot in two years of experimenting in Brooklyn and 
New York ; and the new installation was the last word in equipment 
and acoustical engineering. 

Sam and Jack began making "The Jazz Singer" early in 1927. 
This was to be a feature picture with singing sequences recorded by 
Vitaphone. These sequences were an innovation in feature pictures 
and a tremendous technical achievement. The six words of dialogue 
were ad libbed by Al Jolson at the beginning of a song and were so 
novel that it was decided to leave them in the picture. And on Oct. 
6, 1927, that impromptu speech delighted and thrilled the first- 
night audience in New York City. Talking pictures were a hit. 

But Sam Warner was not there to share in the triumph he had 
done so much to create. He had been working hard, all hours of the 
day and night, for the past two years. He did not feel well enough 
to go to New York for the premiere. A sinus operation developed 
into pneumonia and he died the day before the showing. The entire 
motion picture industry owes a debt to the courage and tenacity of 
Sam Warner. 



Summary. A new 6-mm experimental carbon is described which makes it 
possible to project 2 l / 2 times as much light for 16-mm film as the present 6-mm 
"Pearlex" high-intensity carbons. A 7 -mm "Suprex" carbon offers twice as much 
light as the "Pearlex" carbon and longer burning life than the 6-mm experimental 
carbon. Measurements of radiant energy intensity at the film aperture and spectral 
composition are given. 

The greatly increased usage of 16-mm film for educational and 
entertainment purposes during the past few years has advanced 
this particular phase of motion picture projection to a much 
more significant place in the industry than ever before. 

The use of the small-size 16-mm picture aperture brings with it 
technical problems which require special attention. One of these 
problems is the task of providing adequate light for projection of the 
picture on the screen. The projection of a given amount of light 
through a 16-mm film aperture requires approximately fourfold the 
concentration of radiant energy, compared with 35-mm film. Great 
concentration of light can come only from a source of high bright- 
ness. Fortunately, the 6-mm "Pearlex" high-intensity carbon arc is 
available 1 ' 2 for this task and has proved a valuable tool in the pro- 
jection of 16-mm film. Interest has been shown in still more power- 
ful carbon arc sources. Therefore, attention will be directed in this 
paper toward new developments and possibilities in such sources 
which will make available much greater amounts of light for this 

Present Carbon Arcs for Projection. At present, the carbon 
trim used for 16-mm film projection consists of 6-mm X 8V2-in. 
"Pearlex" positive and 5.5-mm X 6-in. "Pearlex" negative carbons, 

* Presented Oct. 25, 1946, at the SMPE Convention in Hollywood. 
'* National Carbon Company, Fostoria, Ohio. 


448 R. J. ZAVESKY AND W. W. LOZIER Vol 48, No. 5 

operated at 30 amp and 28 v at the arc. This trim, used in a pro- 
jection system employing a 10Y4-in. diameter //1. 6 mirror and a 2- 
in. focus untreated //1. 6 projection lens provides a total of 2300 
screen lumens with no shutter, film or filters. A previous paper 2 has 
shown that this amount of light is capable of illuminating screens of 
75 per cent reflectivity of about 8-, 11. 3-, and 16-ft width, re- 
spectively, to the maximum, optimum, and minimum brightness 
levels of 20, 10, and 5 ft-L recommended for 16-mm film 3 . The 
recommended optimum brightness of 10 ft L is identical with the 
preferred value for viewing 35-mm film as specified by ASA Stan- 
dard Z-^.59-1944. 

"Pearlex" carbons also are designed to furnish a continuous burn- 
ing time of 60 min at the above current and voltage, and have the 
color of the light adjusted toward the quality deemed desirable for 
the projection of Kodachrome. 

Experimental Systems. Consideration has been given to carbon 
arc sources capable of properly illuminating screens considerably 
larger than presently possible in 16-mm projection. 

Experimental work has led to the development of a new 6-mm 
positive carbon capable of operating at currents as high as 50 amp. 
A positive carbon of this type paired with a suitable 5.5-mm nega- 
tive carbon and operated at 50 amp and 40 v, provides 2 1 / 2 times as 
many screen lumens as the present trim with identical //1. 6 optics. 
The significantly greater light output is attributable to a maximum 
crater brightness of 750 candles per sq mm compared with 350 
candles per sq mm for the 30-amp "Pearlex" positive carbon. 

In order to realize this great increase in light output, a positive 
carbon consumption of about 20 in. per hr is reached in comparison 
with 6 in. per hr for the present trim. An 8Y2-m. carbon thus has a 
life of only 15 to 20 min instead of 60 min. 

Since this higher burning rate might limit the application of this 
trim, further work was conducted to relate light output and life at 
lower operating currents. In addition, the effect of using 7-mm 
rather than 6-mm positive carbons was investigated. "Suprex" 
positive carbons were considered for the 7-mm size. 

Comparative screen light output and burning rates are shown 
in Fig. 1 for 6-mm "Pearlex", 6-mm experimental and 7-mm 
"Suprex" positive carbons at various currents. The screen lumen 
values were measured without shutter, film or filters using the 
//1. 6 optics previously described. 

May 1947 










\S6 r#ex 






FIG. 1. Screen lumens and burning rates with carbon arc 16-mm film 
projection systems. 


R. J. ZAVESKY AND W. W. LOZIER Vol 48, No. 5 

It is evident from Fig. 1 that the 6-mm experimental carbon at 50 
amp gives the most light, 5800 lumens compared to 2300 lumens for 
the standard "Pearlex" carbon at 30 amp. In cases where economy 
of power is of great concern, the 6-mm "Pearlex" carbons are to be 
preferred,'for they give the most light in the lower current range. If 
a long burning life is desired and increased power is not objection- 
able, the 7-mm "Suprex" carbon offers advantages. For example, 







'3t '/>*. 


30 32 -34 36 3B 4-O 42 44 46 4-3 SO 52 


FIG. 2. Burning life of indicated lengths of positive carbons. 

to produce a screen light of 4600 lumens, the 7-mm "Suprex" carbon 
requires 50 amp and burns at the rate of 11 in. per hr compared to 43 
amp and 13 in. per hr with the 6-mm experimental carbon. 

Application of New Sources. While it is evident from Fig. 1 that 
significant increases in light can be provided for the projection of 
16-mm film, there are a number of factors incident to such increases 
which must be considered prior to any application of these systems. 
Among these is the time of continuous burning required. Shall this 
be 60 min or shall it be 20 to 25 min, as is the practice for 35-mm film 
projection? Also, there are questions of the color quality of the 


light needed for 16-mm film projection and of the effect on film of the 
radiant energy at the aperture. The proper combination of light in- 
crease, screen size, and desirable continuous burning time involves a 
multitude of factors which cannot be resolved here. However, the 
physical factors such as length and size of carbons, and required 
lamps and mirrors and lenses, etc. have a degree of flexibility which 
can be utilized to best advantage by the industry. 

An example of some possibilities in respect to length of burning 
life is afforded by Fig. 2, where burning life of the positive carbons 
has been plotted against arc current. It will be noted that one hour 
life can be obtained with the S^A-in. length carbon only at the lower 
limits of the indicated current ranges. The 7-mm "Suprex" carbon, 
12 in. long, will give one hour life and 4200 lumens when operated at 
48 amp. This represents an 80 per cent increase in light and the 
same life compared with the 6-mm "Pearlex" carbon at 30 amp. 
The 6-mm experimental carbon, 12 in. long, operated at 50 amp. 
provides 2 1 / z times as much light and about one-half hour instead of 
one hour life. 

The 5800 lumens provided by the 6-mm experimental carbon at 50 
amp is adequate to illuminate a 19-ft screen to the preferred 10 ft L 
value with a shutter having a 50 per cent transmission and without 
film or filters. 

Measurements have been made of the radiant energy intensity at 
the center of the film aperture for the 6-mm "Pearlex" carbon at 30 
amp and the 6-mm experimental and 7-mm "Suprex" carbons at 50 
amp. The technique used was the same as described in previous 
papers 4 published in the JOURNAL. 

The data in Table 1 give the radiant intensity in watts per sq mm 
incident at the center of the film aperture for the systems listed and 
also show the breakdown of the energy in various spectral bands. 
The wavelengths 6300 A, 11,250 A, and 42,000 A are those appro- 
priate to the filters used. In addition, the fraction of the total 
energy within the 4000 to 7000 A wavelength limits of the visible 
region has been calculated from combination with spectral energy 
distribution data in the visible. The maximum intensity of 1.45 
watts per sq mm for the 6-mm experimental carbon at 50 amp is 
greater than the value of 1 .05 watts per sq mm reported in a previ- 
ous paper as a maximum encountered in 35-mm projection. This 
difference is caused mainly by the greater speed of the 16-mm op- 
tical system. 

452 R. J. ZAVESKY AND W. W. LOZIER Vol 48, No. 5 

ro ^ oo ^.^ significance of the levels of radiant 

g *o || e energy intensity listed for items (2) and (5) 

in Table 1 in terms of effect on 16-mm 
film have not been defined completely. 
There is some indication that the smaller 
frame size is better able to withstand the 
distortion from high-intensity radiant 
energy and that with certain precautions 
as described by Kolb, Robertson, and 
Talbot 5 , 16-mm film can be projected 
without heat damage with amounts of light 
discussed in this paper. 

It will be noted also in Table 1 that the 
proportion of energy in various spectral 
bands is about the same for both 50-amp 
arcs (items (2) and (3)). In addition, each 
of these projects has a greater proportion 
of the total energy in the useful visible 
region and so gives less heat per unit of 
w ^ 2 2 2 light than the present standard "Pearlex" 

3. & carbon at 30 amp (item 1). 

^ "S ^ OQ ^^ t^ 

g w rt< co j n addition to these differences in radiant 

3 ^ a energy, the 50-amp sources give a whiter 

U jj co S 8 light than the color modified "Pearlex" 

e carbon, a color similar to that used for 

"b "b *b 35-mm film projection. Here again, the 

; | 1 question of exactly what color quality of 

c | * & ? light will be required for 16-mm film projec- 

g g g B tion remains unanswered. As exemplified 

*. j'Jb ' ky the color modified "Pearlex" carbon, 

% id id >d the color of the light from the carbon 

5 arc can be modified to some extent. The 

"x ~x indications are, however, that such modi- 

<U C <y 

gj "I fications will result in a loss of light per 

'! ^ ,g P unit heat and perhaps a loss in total light 

g g g output, other conditions of operation being 

III equal. 

Although the specific trends and applica- 

| tions of 1 6-mm film projection for the future 

- 2, ^ S are not clearly evident, a demand for larger 


screens and for more light seems certain. This paper has indicated 
that it is possible to extend 16-mm film projection to larger screens 
maintaining recommended light levels. Although such questions as 
continuous burning time, color quality of light, and effects of heat on 
film are still incompletely resolved, there is little doubt that the 
versatile industries in the 16-mm motion picture field can adopt car- 
bon arc equipment to meet the requirements to come. 


1 LOZIER, W. W., AND JOY, D. B. : "A Carbon Arc for the Projection of 16-Mm 
Film", /. Soc. Mot. Pict. Eng., XXXIV, 6 (June 1940), p. 575. 

2 KALB, W. C.: "Carbon Arc Projection of 16 Mm Film", /. Soc. Mot. Pict. 
Eng., XLI, 1 (July 1943), p. 94. 

3 "Recommended Procedure and Equipment Specifications for Educational 
16-Mm Projection", /. Soc. Mot. Pict. Eng., XXXVII, 1 (July 1941), p. 1. 

4 ZAVESKY, R. J., NULL, M. R., AND LOZIER, W. W. : "Study of Radiant Energy 
at Motion Picture Film Aperture", J. Soc Mot. Pict. Eng., 45, 2 (Aug. 1945), p. 

6 KOLB, F. J., ROBERTSON, A. C., AND TALBOT, R. H.: "A Method for Deter- 
mining the Shape of the Image Surface in 16-Mm Projection", presented Oct. 25, 
1946, at the SMPE Convention in Hollywood. 


Summary. The color and persistance of the image formed on the P-7 tube, 
commonly used on radar sets presenting a map-type picture, make it necessary to 
employ different films and techniques in making still and motion pictures. Satisfac- 
tory motion pictures have been made on reversible Super XX film exposed through 
a No. 106 Plexiglas filter in a 16-mm camera equipped with a specially designed f/ 0.7 

Good still pictures can be obtained on fine-grain panchromatic or orthochromatic 
films at f/3.5 without the use of filters, although the use of a blue filter improves defi- 
nition by minimizing "ghost" images not yet completely faded from previous scans. 

An automatic camera permitting the operator to view the tube while pictures are 
being taken has been devised. 

Introduction. The Radiation Laboratory of Massachusetts 
Institute of Technology made a practice of producing a motion 
picture describing the features of each major new radar set it de- 
veloped. One of the greatest problems in the making of these pic- 
tures was to produce a photographic record that reasonably approxi- 
mated the map-type image on the cathode-ray tube as it appeared to 
a person whose eyes had adapted themselves to a low light level. 

Appearance of Map-Type Images. One of the most popular 
methods of presenting radar information in map-like form makes 
use of the PPI, or Plan Position Indicator, in which the image ap- 
pears to be developed by a radial line rotating at a constant speed, 
usually at the rate of from 5 to 20 rpm. The PPI image is an 
almost distortion -free map of the area surrounding the radar antenna. 
Targets which return strong radar echoes, such as cities, appear as 
bright areas on the map. Land areas which do not return very 
strong echoes appear as dimmer areas. Rivers, lakes, and other 
water-covered areas which return very weak echoes appear as dark 

* Presented Oct. 22, 1946, at the SMPE Convention in Hollywood. 
** Vitarama Corporation, Huntington, N. Y. 


areas on the tube. A typical PPI image as it momentarily appears 
to the operator appears in Fig. 1 . 

Because the speed of rotation is so low, radar indicator tubes are 
usually coated with the P-7 cascade screen which retains the image for 
several seconds. At the end of this time the image is almost faded 
from the tube so that a new picture can be generated. 

Characteristics of P-7 Screen Images. The P-7 screen is com- 
posed of two materials coated one over the other. The first coat- 
ing is activated by the electron beam emitting blue light with ex- 
tremely short persistence. The second coating is activated by the 

FIG. 1. Instantaneous appearance of radar image. 

blue light, re-emitting a yellow light of longer persistence. The 
brightness of the persistent image varies inversely with time. 

The light from these two phosphors lies in fairly well-separated por- 
tions of the spectrum, as can be seen from the curves in Fig. 2. These 
curves were determined separately and for convenience the peaks for 
each phosphor have been normalized at 100. Actually the blue, 
nonpersistent light is relatively bright. Since it is seen only in the 
generating trace, and since it is annoying to the operator, the blue 
light is commonly filtered out with a No. 106 or No. 121 Plexiglas 
filter. Transmission curves for these filters are given in Fig. 3. The 
light from each phosphor transmitted by these filters is given in Fig. 4. 

Brightness Range. Since the strength of the echoes returned 



Vol 48, No. 5 

from radar targets varies enormously, the brightness of spots repre- 
senting these targets cannot be made proportional to the strength 
of the signals over the entire range. Usually, after a certain signal 
strength is reached all signals are represented by spots of the same 
brightness. Therefore, there are generally gradations of tone only 
for the weaker signals. To bring out gradations of tone, as in land 
areas, skillful adjustment of the radar controls is necessary. 

The brightness of radar images is so low as to have negligible effect 
on the usual type of exposure meter. However, the brightness of the 







! 5 






WAVELENGTH - millimicrons 

FIG. 2. Emission of P-7 phosphor components. 
These curves were determined separately and the peaks 
were normalized at 100. 

radar image is so low that it has always been necessary to operate the 
tube at maximum brightness in making motion pictures, even when 
the fastest lens and film combinations are used. Still pictures can be 
made with moderately fast lenses. 

Spot Size. Under the best conditions it is possible to resolve 
lines as close as 0.2 mm apart on the 5-in. tube used in airborne 
equipment. For a 7-in. tube the spot is about 20 per cent larger. 
Thus, under best conditions, a 5-in. tube will resolve about 600 ele- 
ments along a diameter, while a 7-in. tube can resolve about 750 
elements. In practice, this resolving power is seldom attained, nor 
is it necessary, since radar detail is often coarser than this. 

May 1947 



Though the behavior of the P-7 tube is much more complicated 
than this simplified description may imply, sufficient information has 
been given to permit a qualitative analysis of the photographic prob- 

Still Photography. The first problem encountered in radar 
photography was the making of single photographs for analysis or 
record. Instantaneous exposures were found impractical because 
parts of the image would have faded from the tube and would con- 
sequently not be recorded. The simple solution was to expose the 






WAVELENGTH millimicrons 

FIG. 3. Transmittance of Plexiglas Nos. 106 and 121 
filters used for viewing P-7 coated tubes. 

film during the entire time required for the trace to go through one 
revolution. Since this time averaged several seconds, it was simple 
to do this with a bulb exposure. Much more uniformly exposed 
pictures resulted, as can be seen in Fig. 5. Later, electrical methods 
were used to synchronize the exposure to the antenna rotation. 

Frame Size. It is obviously desirable to use the smallest frame 
size that will adequately resolve the radar detail. The spot size of 
the cathode-ray tube is the limiting factor. Using the resolving 
power of the tube and the published resolving power data for several 
commonly used films, Table I has been computed showing the 
smallest frame size which will record radar detail : 



Minimum Picture Size 

Vol 48, No. 5 

Super XX 

Panatomic X 

5-In. Tube 

12 mm 
11 mm 
10 mm 

7-In. Tube 

15 mm 
14 mm 
12.5 mm 

Satisfactory recordings can, therefore, be obtained on a 35-mni 
sound frame. Since these figures were based on an optimum spot 



500 600 

WAVELENGTH- millimicrons 

FIG. 4. Portions of P-7 light components transmitted 
by Plexiglas niters Nos. 106 and 121. 

size, satisfactory results for some applications are obtainable on 16- 
mm films if suitable emulsions and processing techniques are used. 
Practical tests have confirmed these conclusions. 

Scopix Camera. The earliest camera was devised simply to allow 
a radar operator to photograph the most interesting scope presenta- 
tions either for record or for further analysis (Fig. 6). It was simply 
a fixed focus 35-mm candid camera mounted at one end of a tube. 
The tube excludes extraneous light during an exposure while holding 
the camera the proper distance from the tube face. In use, the open 
end is held or clamped to the tube face. A bulb exposure is then 
made, keeping the shutter open for'one rotation of the sweep. At 
the Radiation Laboratory, a Kodak 35 camera body was generally 


used with a prefocussed 2-in. Wollensak Velostigmat //3.5 lens. 
Standard 36-exposure cartridges were used. In later models, a data 
chamber containing a data card, watch, and range setting was added. 
O-S-A Radar Recording Camera. In time, it became necessary 
to design a completely automatic camera which would continu- 
ously photograph the same scope the operator was viewing while 
causing him the least possible inconvenience. A camera meeting 
these requirements was designed and built by the Fairchild Camera 

FIG. 5. Radar still picture showing Connecticut shore, 
Long Island Sound, and tip of Long Island. 

and Instrument Company under an NDRC contract with the Radia- 
tion Laboratory (Fig. 7) . This camera was designated the O-5-A by 
the Armed Services. It consists of a camera body, magazine, beam 
splitter, and control box. Adapters and junction boxes have been 
designed to fit the camera to various radar sets. It is compactly ar- 
ranged, since the camera folds back over the radar indicator taking a 
minimum of the operator's space. 

The camera action is synchronized to that of the radar set. Syn- 
chronization can be achieved by several forms of electrical signals 
which can be readily supplied by most radar systems. The radar 



Vol 48 No. o 

operator controls the camera through a small control box containing a 
power switch and a single selector switch controlling the interval at 
which pictures are made. 

The camera records on a 35-mm sound frame the radar picture, a 
data card, counter, watch, range and code lights. The radar image 
is reflected 180 deg by two RCA beam splitters, a feature which allows 
the camera to be folded back compactly. The properties of this 
beam splitter are such that the photographic record is made mainly by 

the blue nonpersistent compo- 
nent while the operator views 
the yellow persistent image. 
The camera uses a 35-mm //2.3 
Bausch & Lomb Baltar lens. 

The magazine holds a 100-ft 
reel of 35-mm motion picture 
film. The film pull-down and 
the film supply and take-up 
functions are separated. Dur- 
ing pull-down, the film loop 
alone is moved by a claw and 
pilot pin arrangement, allowing 
fast pull-down. After the pull- 
down, the take-up and feed 
reels are rotated allowing 
slower acceleration and de- 
celeration for these heavier 
duties, resulting in smoother 
performance. No sprockets 
are used to move the film so 
that the film path is so simple 

that the magazine may be loaded in the dark if necessary. The 
magazine is clamped to the camera body by simple levers, allowing 
rapid and easy change, even by a gloved operator. A photograph 
of an 0-5-^4 frame is shown in Fig. 8. 

Film. In the average case, the cameras used for still radar 
photography are equipped with lenses sufficiently fast so that film 
speed is not a determining factor in choosing a film. Cameras utiliz- 
ing single-frame 35-mm or 16-rtim film are in general restricted to the 
use of finer grain films. Where Leica frame (double-frame 35-mm) 
cameras are used, even resolving power of the film ceases to be a 

FIG. 6. Scopix camera. 


limiting factor. Cameras of this type have yielded photographs on 
Super XX film showing all the detail presented on the 7-in. tubes of 
high resolving power radar sets. 

It is generally impossible to state exactly what the lens diaphragm 
setting must be to obtain the best picture of the radar image, since 
many factors are involved. Some of these factors are the speed of 

(Photograph courtesy Fairchild Camera and Instrument Co.) 

FIG. 7. Fairchild 0-5-^1 radar recording camera. 

rotation of the antenna, the maximum range appearing on the tube, 
and the brightness at which the individual operator prefers to operate 
the tube. Even the ambient illumination has an effect, since it will 
influence the operator in adjusting the image brightness. 


Exposure Table 

(Exposure in f/ units for AN/APS-15 Scopes, 3-Sec Rotation) 


Film No Filter No. 106 (Yellow) No. 121. (Orange) 

Super XX 5.6 2.8 2.3 

Tri-XAero 5.6 2.8 2.0 

Tri-X Ortho 5.6 2.8 1.7 

Agfa Fluorapid 5.6 3.3 1.5 

Recording Neg. Ortho 5.6 2.8 2.3 

Background X-Ortho 4.0 2.0 

Fine-Grain Recording Neg. 4.0 1.7 

Recording Positive 1.7 ... ... 

462 R. C. BABISH Vol 48, No. 5 

The exposures listed in Table 2 are, therefore, intended to show the 
relative sensitivities of the films when photographing the radar image 
directly or through the commonly used viewing filters. The tests 
from which these data were compiled were made with a 16-mm camera. 

It is seen that the differences between panchromatic and ortho- 
chromatic films are not very pronounced when photographs are made 
either with no filter or through the yellow filter. The differences 
appear chiefly those that accompany grain size. Since either filter 
practically eliminates the blue, nonpersistent component of the light, 

(Photograph courtesy Fairchild Camera and Instrument Co.; 
FIG. 8. Frame photographed by 0-5- A camera. 

it is seen that the yellow, nonpersistent image contributes only be- 
tween one-quarter to one-third of the total exposure when photo- 
graphing the bare tube. 

Pictures taken with the slow recording positive film were unsatis- 
factory since the film had a clear base with no antihalation backing. 

Blue Trace Photography. The bulb exposure produces a nega- 
tive which is formed by the combined action of the instantaneous 
blue light of the generating trace and the integrated yellow light 
of the persistent image. The latter contributes roughly from one- 
quarter to one-third of the total exposure. The fact that the 

May 1947 



>ersistent image contributes so much photographically often proves 
indesirable, since images two or three sweeps old may be recorded, 
degrading the image or showing spurious signals. When the expo- 
sure is made through the viewing filter, only the persistent image is 
photographed and the effect is even more pronounced. Where this 
effect is undesirable, only the instantaneous blue trace should be 

This can be done by using a tube coated with the blue phosphor 
alone. Though ideal photographically, it is seldom used because the 
tube cannot also be used for visual work. Films sensitive only to 
the blue light may be used, but these films are generally slow. 









WAVELENGTH millimicrons 

FIG. 9. Transmittance and reflectance of RCA beam- 
splitter used in 0-5-A camera for light at 45 deg inci- 

The P-7 tube can be photographed through a blue filter placed 
over the lens. Almost any of the Wratten blue filters are suitable 
since even the light blue filters cut down the persistent image to a 
reasonably low value. Most effective are the Wratten filters Nos. 
34, 39, and 47, which require about two stops more exposure. Even 
better are the Corning glass filters Nos. 5030 and 5543 which also 
require almost two stops more exposure. 

More interesting is a beam splitter produced by RCA which re- 
flects a high percentage of blue light and a low percentage of yellow 
light. On the other hand, it transmits a high percentage of yellow 



Vol 48, No. 5 

and a low percentage of blue. It can, therefore, be used to divide 
the light between two separate paths, one of which is more suited for 
photographic and the other for visual work. This beam splitter 
coating is used for both reflectors in the 0-5-^4 camera. The in- 
crease in exposure required when this filtering method is used is less 
than two stops. Color curves are given in Figs. 9, 10, and 1 1 . 

Making the Exposure. Of the several factors operating to cause 
variations in the brightness of radar images, the one most trouble- 
some is the personal factor. It is generally best to have the operator 





WAVELENGTH- millimicrons 

FIG. 10. Portions of P-7 light components transmitted 
by RCA beam-splitter. 

make several test strips under operating conditions to determine the 
aperture at which he gets best general results. The latitude of the 
film can usually accommodate the other variations. It is better to do 
this than to try to force him to decide what brightness will photo- 
graph best at a given //number. However, if the operator finds 
that the aperture setting falls much below//5.6 when photographing 
the bare tube, he should seriously consider whether or not he is 
operating the tube at too high a level. If this is the case, spot size 
may be increased and "blooming" may be in evidence, resulting in 
loss of detail. On some of the higher resolving power sets using the 
7-in. tube, best results are obtained when the lens setting is around 
//3.5 on Super XX film. 

May 1947 



Processing. After exhaustive tests best results were found to be 
obtained when the directions on the package were followed. For 
16-mm or 35-mm films, fine-grain developers of the D-76 type should 
be used. When paper prints are to be made, best average results are 
obtained when the film is developed to a gamma of about 0.8. If a 
motion picture print is to be made, development to a lower gamma 
might be advisable. High contrast development of map-type pic- 
tures should be avoided except where the picture is composed of a 
simple pattern of lines or points. Fig. 5, showing the tip of Long 











WAVELENGTH millimicrons 

FIG. 11. Portions of P-7 light components reflected by 
RCA beam-splitter, after two reflections. 

Island and the coast of Connecticut, was reproduced from a high 
definition 7-in. scope on Leica frameSuperXXfilmat//3.5. It was 
developed to approximately 7 = 0.8 and printed on No. 3 paper. 

Viewing. For selecting the frames to be printed from reels of 
16-mm or 35-mm film, Recordak or Microfilm viewers can be used. 
Better yet, advantage can be taken of the fact that the pictures are 
made on motion picture film by projecting the films as motion pic- 
tures yielding highly speeded-up records of the radar mission. 

Motion Pictures. In making radar still pictures it was found 
desirable to photograph the instantaneous blue component of the 
emitted light. However, in making motion pictures, it is necessary 
to photograph the much weaker persistent image, which is what the 

466 R. C. BABISH Vol 48, No. 5 

operator actually views. It is desired to show the image just dis- 
appearing from the screen in the area just preceding the generating 
trace. For still pictures, an exposure of several seconds at//2.8 was 
required to photograph the persistent image. Because parts of the 
image have faded to very low brightness levels, a lens much faster 
than f/2.8 is required for making motion pictures, even if the tube is 
operated at a brightness level considerably above normal. 

Polaroid Lens. For making scope motion pictures a lens was 
especially designed by the Polaroid Corporation of Cambridge, 
Massachusetts. This lens has a focal length of approximately 2 in. 
and an aperture off/0.7. Its design includes a plastic Schmidt-type 
aspherical correcting element. 

FIG. 12. Cine-Kodak Special fitted with Polaroid 
//0.7 lens for radar photography. 

The results of a test made on this lens by the Army Signal Corps 
are given in Table 3. 


Equivalent Transmission Aperture f/' 0.64 

Resolving Power 

Axial 300 lines per mm 

2 . 5 deg 252 lines per mm 

5 . deg 224 lines per mm 

7 . 5 deg 80 lines per mm 

10 deg 56 lines per mm 

Since the cathode-ray tube screen is convex towards the lens, and 
since at this aperture and the customary close working distances the 
depth of field is extremely shallow, the results are not quite so good 


as the results of this test might lead one to expect. The picture is 
adequately sharp for the purpose, however. 

Camera. This Polaroid lens is fitted to a Kodak Cine*-Special 
16-mm camera. It has 200-ft magazines and has motor drives 
operating from 110 v a.c., and from 24 v d.c. The camera and lens 
are shown in Fig. 12. 

Film. A search was made for the film most sensitive to light 
of the color of the persistent image. Eastman Kodak Company 
co-operated fully in this manner, sending several rolls of film, some 
of which were standard emulsions and some of which incorporated 

FIG. 13. Electronic photometer used for meas- 
uring the low light levels encountered in radar 

special dye sensitizers. These were all exposed in the same camera 
running at one speed, to the same picture on tube testing laboratory 
equipment which was first allowed to run for some time to ensure 
stable operation. These films were returned to Eastman Kodak for 
processing to gamma 0.8. The resulting films were projected simul-. 
taneously with the Super XX negative as a standard so that com- 
parisons could be made. Several conclusions were reached : 

(7) One sample emulsion N4X-15753, a Tri-X type with 
special dye sensitizer, showed greater speed than the Super XX 
reversal film No. 2601 used as the standard. The sample film 
was much too grainy for use in 16-mm size, however. 

(2) Standard Super XX reversal developed as negative and 



Vol 48, No. 5 

standard Tri-X were equally sensitive. Tri-X had a higher fog 
density and showed appreciable grain. 

(3) No emulsion but the one mentioned was faster than 
Super XX Reversal. Those equally fast were either grainier or 
had no particular advantage in other respects to warrant using 
the special emulsion. 

FIG. 14. Reflector used to control separately the levels of illumina- 
tion on the scope face and on the surrounding area. 

As a result of this test, Super XX Reversal No. 2601 has been used 
exclusively for making motion pictures of P-7 scopes at the Radiation 

Operation of Radar Indicator. While it would be most desirable 
to operate the tube at normal brightness, it proves necessary to 
operate the tube as high as possible. The tube brightness is adjusted 
to just below the point at which a faint halo begins to appear around 
the generating trace. This halo might appear to be too dim to re- 
cord on the film, but it is actually dim only in comparison to the 
generating trace. It is often overlooked, Actually, it is as bright 

May 1947 



as the persistent image not many degrees removed from the gen- 
erating trace, and will appear in the projected image. 

Face Lighting. The Naval Photographic Science Laboratory 
first published data on a 
method by which more of the 
extremely faint portions of 
the radar image could be 
recorded photographically. 
Auxiliary lights are used so 
that the tube face is illumin- 
ated slightly. Tests made at 
the Radiation Laboratory con- 
firmed the results claimed in 
the PSL report One experi- 
ment was conducted on a 12- 
in. tube on which a short- 
range sweep was rotated at 
6 rpm. The angle through 
which radar detail could be 
seen was almost doubled in 
that part of the test in which 
face lighting was employed. 
There is a further psycho- 
logical advantage in employ- 
ing face lighting. The entire 
tube face is reproduced at a 
low brightness level, much as 
the operator sees it, giving a 
sense of completeness to the 
picture previously lacking. 

Photometer (Fig. 13). 
When making motion pic- 
tures at //0.7 the illumina- 
tion required for face lighting 
is lower than can be read 

with an ordinary exposure FIG- 15. Strip of motion picture 

, . film snowing radar map of shoreline of 

meter. Lacking other means Massachusetts. 

of measurement, Prof. W. B. 

Nottingham of M.I.T. adapted for our use a very sensitive self-con- 
tained photoelectric meter which he had designed. With this 

470 R. C. BABISH Vol 48, No. 5 

meter, it was even possible to measure the brightness of small 
areas of the radar image. A unique feature of the device is its inte- 
grating circuit by means of which low levels of light can be measured 
by its action over a measured period of time. Direct reading scales 
are also provided for the higher light levels. 

Methods of Photographing Indicators. At first, a method first 
published by PSL involving a double exposure was used. The tube 
face was first covered with black cloth or paper. The console area 
surrounding the tube was then photographed in subdued light so that 
the finished print would convey the impression that the tube is in a 
darkened room. The film was then rewound, the black cloth re- 
moved and the radar image and face lighting adjusted to the proper 
level. A second exposure was then made. 

This method was later abandoned since many of our pictures were 
made under severely adverse conditions when the fairly delicate ar- 
rangement of lights, masks and camera was often inadvertently dis- 
turbed. A simpler method was devised, enabling the console and 
radar set to be photographed at the same time. 

The problem in single exposure photography was to control two 
contiguous areas of illuminations, that on the console and that on the 
tube face itself. Since the illumination on the tube face is relatively 
low, its boundary did not need to be sharply defined. In our work 
the scope face is almost always photographed so as to nearly fill the 
height of the screen, further simplifying the problem. 

T. F. Hartley, the cameraman who actually photographed most of 
the motion pictures of scopes at the Radiation Laboratory, solved the 
immediate problem by producing a light reflector shaped much like 
an oversized cake ring. (Fig. 14.) Inside this ring, twelve 7 J /2-w 
lamps were arranged symmetrically about an adjustable central 
cylinder. In use, the reflector is placed close to the tube face and 
aligned so that the axes of the cylinder and the scope coincide. If 
the lights are now turned on, the console is uniformly illuminated 
except for the circle masked by the cylinder. Two other lamps in 
reflectors are set up behind the reflector so as to direct light into the 
rear of the cylinder. This light rereflected from the inner wall of 
the cylinder, provides flat face lighting. Both sets of lamps are pro- 
vided with independently variable voltage sources for controlling the 
levels of illumination. The method proved to be simple and yielded 
results superior to those previously obtained. An enlargement of 
several frames taken by this method is shown in Fig. 15, 


Filters. A No. 106 Plexiglas filter is used to cut down the blue 
light appearing in the generating trace, which because of its rela- 
tively high intensity causes the trace to photograph as a much 
broader line. The No. 121 Plexiglas filter usually mounted over the 
face of the screen should not be used since it is much denser than 
necessary. (See Figs. 3 and 4.) 

Processing. In processing still pictures which might be con- 
sidered as integrated exposures of a number of motion picture 
frames, it was found desirable to- develop the negative to a gamma of 
0.8. Because the brightness of the radar image fades with time, the 
image contrast of a single motion picture frame which must record 
this added effect is greater than that of a still picture". Therefore, 
it would appear that the motion picture negative should be developed 
to an even lower gamma. However, since face lighting artificially 
reduces the contrast of the scope image, best results have been ob- 
tained when the negative is developed to a gamma between 0.8 to 
0.9. The frames shown in Fig. 15 were developed in this manner. 
The foregoing statements apply principally to map-type images 
photographed by the Polaroid //0.7 lens which is capable of giving 
nearly the proper exposure. When negatives are made with slower 
lenses forced development is generally necessary to obtain reasonably 
good results. 

In cases where the radar picture is composed principally of lines or 
spots, forced development can sometimes be used to good advantage 
to accentuate these simple details even when photographed by the 
Polaroid lens. 

Since the high speed of the Polaroid //0. 7 lens and the employment- 
of face lighting techniques yield almost correct exposures, the need 
for special manipulation of the negative has been reduced. Con- 
sequently, the last motion pictures of radar scopes produced at the 
Radiation Laboratory were given the normal reversal treatment at 
Rochester yielding superior results. 

Color Photography. Results obtained by the method outlined 
above were so gratifying that, just prior to the termination of the 
Radiation Laboratory, an attempt was made to photograph the 
same radar image shown on Fig. 13 on Kodachrome. Surprisingly 
enough, the persistent image was recorded through about 90 deg of 
the tube face. If time had permitted, the faster color films developed 
for the armed forces and face lighting filtered to match the color of 
the persistent image, might well have yielded color photographs of 

472 R. C. BABISH 

sufficiently good quality to replace the black-and-white scope pic- 
tures which have marred the finish of our Kodochrome motion pic- 

Acknowledgment. Investigation of various phases of this work 
were carried out under the direction of Carl F. J. Overhage and 
Charles Newton, Group Leaders at the Radiation Laboratory. 
Clifton Tuttle, of Eastman Kodak Company, collaborated exten- 
sively in investigations of fast lenses and films for motion picture 
use. Irving Doyle, chief engineer of the Fairchild Camera and In- 
strument Company and designer of the 0-5-A camera, supplied the 
photograph of the 0-5-^4 camera and the RCA beam-splitter curves. 
All photographs except those noted above were obtained from the 
Radiation Laboratory, Massachusetts Institute of Technology. 


Summary. Cross-banding of reels between exchange and theater calls for some 
reform to eliminate the confusion caused by this inefficient method. The paper de- 
scribes a proposed film lock and immediate identification which becomes an integral 
part of the film itself. 

In handling motion picture film, it has always been a problem to 
hold the film against unwinding either temporarily or permanently. 
Various expedients, such as metal clips which scar the film, rubber 
bands which mark the film upon deterioration, small clamps, and the 
like, have been used for this purpose. 

Release prints are bound with a paper band which is wrapped 
around the reel and held in place by a string. As the band usually 
contains the data relative to the film, and as they must be removed 
each time the film is used or examined, and since each band fits only 
its particular reel, it must be replaced upon the exact reel or con- 
fusion results. 

The proposed film lock is an integral part of the film so there is no 
possibility of misapplying the data relative to the films as the lock 
becomes a part of its respective reel. 

The film lock amounts to forming a tongue on the end of the film 
with a groove or series of grooves formed in the body of the film adap- 
ted to receive the tongue, so that the outer strand of film may be locked 
on itself by inserting the tongue through one of the grooves. The 
friction of the tongue between the strands of the roll will prevent 
the tongue from withdrawing and the normal tendency of the film 
roll to expand will exert a continuous pressure so that the tongue will 
be permanently locked in place and the reel will not unwind until the 
tongue is actually withdrawn. The tongue is forced into the slots 
merely by a pressure of the thumb around the outside strand of the 
film until it encounters the slot, whereupon it is worked into the slot 
and fixed between the two outer strands of the roll. After it is once 

* Presented Oct. 25, 1946, at the SMPE Convention in Hollywood. 
** Twentieth Century-Fox Film Corporation, Beverly Hills, Calif. 




Vol 48, No. 5 

locked, it will remain indefinitely and is easily released merely by 
withdrawing the tongue. 


FIG. 1. Proposed new identification reel band. 

The lock may be used repeatedly and will find usefulness not only 
for temporarily locking rolls against unwinding during handling in the 
cutting rooms or for inspection, but will serve as a permanent lock for 
holding rolls of film of either small or large diameter against unwind- 

FIG. 2. Cutaway showing tongue and groove of proposedjfilm lock band. 

ing when stored permanently. It also provides a means of attaching 
the data relative to each film permanently to its respective film so that 
there is no chance of misapplied data caused by separating a roll of 
film from its respective wrapper. 





FIG. 3. Film lock completed. 

A simple punch quickly accomplishes the forming of the tongue and 
groove in a single operation, and in practice, film locks could be made 
and kept in stock and spliced onto their respective reels, or they could 
be made an integral part of the film itself. 


I wish to extend thanks to the many individuals who have given 
their co-operation in developing this proposal. 


DR. C. R. DAILY: I should like to know whether this band has been given an 
exchange trial yet. 

MR. SCHWARTZ: No, but I have given it an exhaustive test at the studio. 
Various questions were raised as to the possibility of the tongue becoming worn 
or torn, and the question of the operator tearing off the ends. So far as the 
operator is concerned, I have no answer. So far as the wear and tear of the film 
is concerned, I did allow the film to flap on a metal bench 1500 or 2000 times, 
which was an even more drastic test than the usual flapping of the film in the 
lower magazine of the projector or in the rewind box in the booth. I cannot 
give any particular reason why the film stood up to wear and tear, except the 
fact that there was a lesser film surface concerned in threading and rewinding the 
film in the tests that I made. I placed the tongue into the slot on the reel as 
far as it would go, and then by exerting extreme pressure I pulled the film in 
such a fashion that normally the film would tear. To my surprise, it did not. 
To make the comparative test, I used the normal full width leader under the same 
circumstances and after the thirty-fourth time the film did tear. 

MR. E. DENNISON: I have done a lot of research on handling film in exchanges 
for a period of twenty years, and I have also had many ideas as to how to keep 
the ordinary paper film band from being a nuisance to the operators and inspectors 
in exchanges. I think your idea of the lock is very good, but I think you are go- 
ing to have the same human element to contend with as you had with the film. 
Several things have been evolved in the past years. One was the steel band. 
Some others had ideas of getting away from the ordinary paper band with the 
string and the button on it. I think you are going to have to educate every in- 
dividual projectionist in the United States to use something different. 

MR. SCHWARTZ: We know that from time to time we have damaged film 
come back because the operator just got mad. He could not get the film into the 
slot, so he tore another piece and another piece, and he had no concern about the 
film itself. I do think if we help him with the film lock, or some other method 
that may be adopted, he will feel we are with him and trying to help him in some 
way. The present method has been a drawback in many, many ways. More 
often than not the operator will take all the bands off of the reel and stick them 
down in the side of the container and just forget them. This proposal is an at- 
tempt to improve the method of identifying film, and holding the film from 
unraveling, so perhaps some method can be found whereby we can help to edu- 
cate the operator to be a little more concerned about the film. If we are helping 
him, I am sure he will help us. 



Summary. The unprecedented volume of Navy combat film photographed during 
the war presented serious problems of co-ordination, cataloging, and filing. This 
paper outlines briefly the inception and organization of the U. S. Navy Film Library, 
the mission of which is the preservation and custody of all Navy Combat Film. 

For the first time in the history of warfare, motion pictures became a 
universal medium in the field of actual combat. The unprecedented 
volume of combat film, running into millions of feet, photographed 
by the Navy during the war years, presented several serious problems 
of which preservation and future utilization were the most pressing. 
Anticipating the relative magnitude of this new activity, a Motion 
Picture Film Library was organized as a unit of the U. S. Naval 
Photographic Center at Anacostia, D. C., until very recently, known 
as the Photographic Science Laboratory. The mission of this organ- 
ization was the custody 'and preservation of all Navy motion picture 
combat film as well as its co-ordination for immediate and future 

It was evident at the outset that the paramount factor in any 
system devised to catalog and file this type of material must be its 
preservation in terms of authentic locale. Since almost every ship in 
the combat areas carried on some photographic activity, our sources of 
material ran well into the hundreds. This film represents a doc- 
umentary record of naval action during this period, and the only 
means of preserving its authenticity was to assemble each activity's 
film into separate rolls, and catalog it as such. This method of as- 
sembly meant that the combining of like material that is, grouping 
all shots of deck crashes, close-ups of gun crews in action, etc. would 
be impossible, although it would have made future reference and re- 
search somewhat easier. Under ordinary circumstances, this could 

* Presented Oct. 22, 1946, at the SMPE Convention'in Hollywood. 
** U. S. Naval Photographic Center, Anacostia, D. C. 


have been accomplished; but the tremendous volume and wide 
variety of subject matter being received each day would have made 

DATE OF SCREENING: 5/14/46 Ham. 

INDEX ft 16820 


NEG: 1-5820 POS: 2-5820 DUPE NEG: 

MASTER: 16 MM: LENGTH: 462ft. 


1) MCU Awards being given to men; men lined up at quarters. 

2) GV Band playing. 

3) GV Men lined up topside submarine. 

4) GV-UA Photographer topside conning tower submarine. 

5) GV-UA Flag with three stars flying from periscope of submarine. 

6) MCU Officers in white lined up. 

7) MCU Officers and men lined up at quarters topside submarine. 

8) CU Adm. speaking over mike. 

9) GV-MCU Lt. Comdr. presenting three-star flag to a general. 

10) GV Officers on dock saluting. 

11) GV Officers lined up topside submarine, saluting. 

12) GV Band playing, Adm. FG saluting. 

13) GV Officer reading over microphone. 

14) MCU Officers lined up aboard submarine receiving decorations 



SSs, gen. OPTICS, periscope 


AWARDS, presenting COMM. AFLOAT, radio 


FIG. 1. Sample review sheet. 


. it an almost impossible task even for a highly trained and well-staffed 

The initial functions under this system were the deletion of evident 



Vol 48, No. 5 

"N. G." footage and the assignment of a permanent numerical index 
number to each roll. The prints were then screened and a scene-by- 
scene description taken by means of a dictaphone. At the same time 
the current classification and quality were established. This record 
was then reduced to a typewritten review sheet, listing the index 
number assigned that particular roll of film. Copies of this review 
sheet were immediately made available to all authorized agencies. 
As a result, within a matter of hours after the film reached the library, 
selections of material could be made simultaneously by the several 
groups charged with the compilation of photographic combat reports 


ct.ssificTio RESTRICTED 

~USS iT SHANORI-LA (CV-33) ' 8/27/45 

[""4 -62 ie (s) ^-tSTuii rT-'egi? (s) ""color " |J5 ?i ft! 


SHATWRI -LA"? ffsf" 

1) AV Task force underway. Erit'ish DD seen below on surface. 

FIL-S, 16mm color 

2) AV t.!any components of the task force underway, DDs, air 
craft carriers, heavy cruisers seen entering Sagaml, Guam 
Bay, coast of Japan seen in PG. *& 
3) AV British BE, K^S Kir.'G GKORC"? V, underway. 
4) AV USS MISSOURI underway. 
BBt^^V DD coming alongside the Missouri for transferring per- 
sonnel at sea. 
gUJ^AV DD alongside the USS rUSSOUPI-SV. 
7) AV-MS British DD underway. 
8) AV Yokasuka naval base, Japanese EB Vagato seen anchored 

HARBORS, Tokyo Bay 
SHIPS, FOR., British DD 
"DESTROYERS, DD, underway 
AIR CARRIERS, CV, underway 
CRUISERS, CA, underway 
HARBORS, Sagami.Bay, Guan- 
Kl;;c GEORGE V, ?WS 
BBs, underway 
TRANS. AT SEA, personnel 

9) AV Number of industrial cities in & around Yokahama 
10) AV Yokahama sea plane base, Jap plane seen on field 

SHIPS, FOR., Japanese 
PTTTFS Yokflhima 

11) AV FOW camp near Yokahama sea plane base 
13) AV USS taSSOURI, shore line of Yokasuka naval base seen 

PLANES, FOR., Japanese 
PRISONS, Yokahama 


mini Good. 

Fig. 2. Cross-reference index card. 

and the release to the public, through the various news channels. 
(See Fig. 1.) The task of immediate availability having been ac- 
complished, the review sheet was then edited by means of an alpha- 
betical cross-reference index. This index covers over 500 main 
headings and approximately 2500 subheadings, which had to be de- 
veloped before the process of cataloging and filing could be carried 
through to completion. As an example: "Ships" is a main heading, 
the first subheading will be types of ships, under this heading will 
follow others covering the various activities such as DEs underway, 
firing, burning, exploding, sinking, etc. All of the cards under each 
subheading are, in turn, separated as to original type of film, that is, 
35-mm black-and-white, or 16-mm black-and-white, or color. (See 
Fig. 2.) 



It will be noted that the index number, the origin (ship or station), 
the date of action, a title covering the general subject matter, and the 
vault location of all film both original and duplications under this 
number appear on the card. The cross-references are listed on the 
right-hand side, one of which is arrowed. To minimize the reading 
time in the selection of stock footage, the arrowed items on the left 
indicate the material covered by the arrowed cross-reference. Thus, 
as the completed card reaches the alphabetical file, the material it 
covers becomes immediately available. To augment the alphabet- 
ical index and at the same time expedite the initial filing of the film in 
the vaults and the handling of immediate requests originating from 
copies of the original screening account, a numerical file was es- 
tablished. This cardex file lists, in numerical order, every roll of film 
that has been reviewed. A temporary card listing only the type of 
film and its vault location is used until such time as it can be replaced 
with the completed card. 

To ensure the maximum degree of physical preservation, the U. S. 
Naval Photographic Center is equipped with 62 modern air-condi- 
tioned film vaults. Temperature and relative humidity of 68 and 50 
respectively, are maintained 24 hours a day. 

In an effort to utilize the maximum vault space available, a system 
of can numbers was devised whereby a number of small rolls car- 
rying different index numbers were assigned the same can number in 
a given vault. This meant that a 100-f t roll of film was not occupy- 
ing the space that could have been utilized by four or five additional 
rolls of similar size. 

As an added precaution original negative and any duplicating 
material covering it is never filed in the same vault. The Library 
Annex, only recently completed, now houses the present library staff 
and 36 of the existing vaults. At present, the Navy has on file ap- 
proximately "twenty-five million feet of combat film and since the 
Library is the depository for all Navy film having historical value, 
the files are constantly expanding. While the foregoing has dealt 
exclusively with motion pictures, there are presently over a million 
still and aerial negatives and prints covering the various combat 
activities which have been cataloged and filed in basically the same 

The primary function of this film is, of course, its utilization in the 
Navy's postwar training program. Into almost every training film 
is incorporated some measure of this material. The interest it 

480 G. L. SARCHET 

stimulates and the parallel it provides between training and actual 
combat are invaluable. 

Rapid demobilization has delayed, to some degree, the Navy's 
program of making pictorial material available to the public through 
educational institutions, research organizations, and the motion 
picture industry. 

This material is being made available to such agencies by author- 
ization of the Office of Public Information, under the supervision of 
the Secretary of the Navy. 



The editors present for convenient reference a list of articles dealing with subjects 
cognate to motion picture engineering published in a number of selected journals. 
Photostatic or microfilm copies of articles in magazines that are available may be 
obtained from The Library of Congress, Washington, D. C., or from the New York 
Public Library, New York, N. Y., at prevailing rates. 

American Cinematographer 

28, 3 (Mar. 1947) 

Composition in Motion Pictures (p. 84) 
The Zoomar Lens (p. 87) 
"13 Rue Madeleine" (p. 88) 
The Cinema Workshop 9. Color Cinematograph (p. 92) 

C ommunications 

26, 12 (Dec. 1946) 

Placement and Operation of Microphones in Broadcast 
Studios (p. 12) 

27, 2 (Feb. 1947) 
Lateral Recording (p. 26) 


20, 3 (Mar. 1947) 
Experimental C-R Tubes for Television (p. 112) 

Ideal Kinema 

13, 140 (Mar. 13, 1947) 
B.T.H.'s New Projector (p. 23) 




International Projectionist 

22, 2 (Feb. 1947) 

"Quality" versus "Pleasing" Sound Reproduction (p. 5) 
Simultaneous All-Electronic Color Television (p. 8) 
Magnetic Recording, Reproduction Data (p. 14) 

22, 3 (Mar. 1947) 

Studio Super H.I. Carbon Arc Lamps (p. 7) 
Magnetic Recording Symposium by Academy (p. 9) 
Television, Films and the Human Eye (p. 14) 




Radio News 

37, 3 (Mar. 1947) 
The Recording and Reproduction of Sound (p. 52) O. READ 

37, 4 (Apr. 1947) 

The Recording and Reproduction of Sound (p. 50) O. READ 

Magnetic Sound for Motion Pictures (p. 12) M. CAMRAS 



An interesting seminar was held by the Midwest Section of the Society in 
Chicago on May 8, 1947, devoted to "Optical Systems for Motion Pictures". 
R. E. Lewis, Secretary-Treasurer of the Section, served as moderator. Others 
who contributed to the session were E. E. Bickel, chief optical engineer, Simpson 
Optical Manufacturing Co.; R. F. Mitchell, assistant chief engineer, Ampro 
Corporation; A. M. Smith, assistant optical engineer, Bell and Howell Co.; 
and R. A. Woodson, assistant chief optical engineer, Bell and Howell Co. 

Among the items discussed by the group were limits of lens design usefulness, 
difficulties with mechanical clearance for optics, movement of the film in the focal 
plane, as well as various sound reproduction systems and related problems. 

A paper by J. A. Maurer, of J. A. Maurer, Inc., entitled "General Principles 
of Optical Recording on Film" was read by R. T. Van Niman of Motiograph. 
This was a transcription of a talk which Mr. Maurer gave previously before the 
Acoustical Society in Chicago. 

Active discussion from the floor indicated the popularity and success of the 
seminar type of meeting, held in the rooms of the Western Society of Engineers. 


Again we have heard of the availability of sets of back issues of the JOURNAL 
and we are passing this information along to interested members. Many issues 
are now out of stock and we are glad to co-operate in finding purchasers for, the 
sets listed below. All details concerning price, payment, etc., must be arranged 
direct with the owners given. 

John J. Kuehn, 728 Buckingham Place, Chicago 13, 111., has a complete set of 
bound JOURNALS through 1944, and unbound copies for 1945 and 1946. 

Philip H. Hiss, "Cedarcrest", New Canaan, Conn., has many of the early 
Transactions which are now out of print, and JOURNALS from 1930 to August 

Both of these sets must be purchased complete, the owners do not wish to sell 
separate volumes or issues. 

We are grieved to announce the death of Ernest S. Lundie, Active 
member of the Society, on March 11, 1947, in Glenside, Penna. 


Vol 48 JUNE 1947 No. 6 



Proposals for 16-Mm and 8-Mm Sprocket Standards 

The Projection Life of 16-Mm Film C. F. VILBRANDT 521 
Effect of Time Element in Television Program Opera- 
tions H. R. LUBCKE 543 
Lighting and Exposure Control in Color Cinema- 
tography R. A. WOOLSEY 548 
Motion Pictures on Operation Crossroads 


A High-Quality Recording Power Amplifier K. SINGER 560 
A Method for Determining the Shape of the Image 
Surface in 16-Mm Projection 

The Simulation of Radar Presentations for Briefing 

Purposes J. WESTHEIMER 586 

Current Literature 591 

Society Announcements 592 

Supplementary Membership Directory 594 

Index to Journal, Vol 48 (January- July, 1947) 

Author Index 602 

Classified Index 605 

Copyrighted, 1947, by the Society of Motion Picture Engineers, Inc. Permission to republish 
material from the JOURNAL must be obtained in writing from the General Office of the Society. 
The Society is not responsible for statements of authors or contributors. 

Indexes to the semiannual volumes of the JOURNAL are published in the June and December 
issues. The contents are also indexed in the Industrial Arts Index available in public libraries. 










**President: LOREN L. RYDER, 

6451 Marathon St., Hollywood 38. 
**Past-President: DONALD E. HYNDMAN, 

342 Madison Ave., New York 17. 
** Executive Vice-President: EARL I. SPONABLE, 

460 West 54th St., New York 19. 
^Engineering Vice-President: JOHN A. MAURER, 

37-01 31st St., Long Island City 1, N. Y. 
** Editorial Vice-President: CLYDE R. KEITH, 

233 Broadway, New York 7. 
^Financial V ice-President: M. RICHARD BOYER, 

E. I. du Pont de Nemours & Co., Parlin, N. J. 
** Convention Vice-President: WILLIAM C. KUNZMANN, 

Box 6087, Cleveland 1, Ohio. 
** Secretary: G. T. LORANCE, 

63 Bedford Rd., Pleasantville, N. Y. 
^Treasurer: E. A. BERTRAM, 
850 Tenth Ave., New York 19. 


**JOHN W. BOYLE, 1207 N. Mansfield Ave., Hollywood 38. 

*FRANK E. CARLSON, Nela Park, Cleveland 12, Ohio. 

*ALAN W. COOK, Binghamton, N. Y. 
**ROBERT M. CORBIN, 343 State St., Rochester 4, N. Y. 
**CHARLES R. DAILY, 5451 Marathon St., Hollywood 38. 
*tjAMES FRANK, JR., 356 West 44th St., New York 18. 

*JOHN G. FRAYNE, 6601 Romaine St., Hollywood 38. 
**DAVID B. JOY, 30 East 42d St., New York 17. 

*PAUL J. LARSEN, 1401 Sheridan St., Washington 11, D. C. 

*WESLEY C. MILLER, MGM, Culver City, Calif. 
**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood. 
*JA. SHAPIRO, 2835 N. Western Ave., Chicago 18, 111. 
*WALLACE V. WOLFE, 1016 N. Sycamore St., Hollywood. 

*Term expires December 31, 1947. tChairman, Atlantic Coast Section. 
**Term expires December 31, 1948. tChairman, Midwest Section. 
"Chairman, Pacific Coast Section. 

Subscription to nonmembers, $10.00 per annum; to members, $6.25 per annum, included in 

their annual membership dues; single copies, $1.25. Order from the Society at address above. 

A discount of ten per cent is allowed to accredited agencies on orders for subscriptions 

and single copies. 
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers, Inc. 

Publication Office, 20th & Northampton Sts., Easton, Pa. 

General and Editorial Office, Hotel Pennsylvania, New York 1, N. Y. 

Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa. 

under the Act of March 3, 1879. 


Vol 48 JUNE 1947 No. 6 



Summary. On Nov. 8, 1945, the chairman of the SMPE Standards Committee 
appointed a Subcommittee on 8-Mm and 16-Mm Projector Sprockets with the task 
of revising the present American Standards for sprockets. The personnel of the 
subcommittee is Otto Sandvik, chairman; Herbert Barnett, John A. Maurer, Law- 
rence T. Sachtleben, and Malcolm G. Townsley. This paper, however, is not a 
report by the members of the subcommittee, but is material prepared for their con- 

The ASA Sectional Committee on Motion Pictures, Z22, had earlier referred the 
sprocket standards to the Standards Committee for reconsideration, suggesting that 
the specifications should be in equation form. In this paper, the authors have followed 
this procedure and are submitting proposals for a new standard, as shown in Fig. 1 . 
Formulas are given for the root diameter of the sprocket and for the thickness and 
shape of the tooth. In these formulas due allowances are made for variables such as 
the pitch of the film, the path of the film, and the number of teeth on the sprocket. 
Careful consideration is given to lateral dimensions. 

Members of the Society and others interested in sprocket design are urged to read 
this paper and Dr. C. F. Vilbrandt's paper, beginning on page 521 of this issue, 
and to submit their comments to Boyce Nemec, SMPE Engineering Secretary. 

In October 1945, Committee Z22 of the American Standards Asso- 
ciation reviewed all the existing standards for motion pictures. Some 
were accepted, either as they had been written or with minor correc- 
tions, and were reissued as 1946 Standards. Several were referred 
back to the Committee on Standards of the Society of Motion Picture 
Engineers for revision. Among these were Z22.6-1941 and Z22.18- 
1941 covering 16-mm and 8-mm film sprockets, respectively. They 
were returned with the suggestion that the substitution of formulas 

* Presented Oct. 25, 1946, at the SMPE Convention in Hollywood and Apr. 25, 
1947, at the SMPE Convention in Chicago, 111. 
** Eastman Kodak Company, Rochester, N. Y. 




Vol 48, No. 6 





rt ^ 






d <u 

03 CJ 


O " C 

o i-. cj 




3 ^ iq 



O iv 

o S 



oo en 

cp * ' CM 

O Q 


CO * ll 

^ 5 



* OQ 0> 

do CJ 
m + i o 
m Q 

CJ ?J ^ 

6 O 
.. Q 





O cj 



do oo 

0> 6d K> 
CD * p 

& CD b 











P 6 
- I 

rS CD 10 



Q. Q 


n ii 
0. Q 


O. Q 


nl o 



i m 


= Q 

o> * 










^ I- en 





d jj. n *d v~- x-> 
a^^d uj z to !. 

u. LJ 

i-. t- U) 2 

*^ * UJ ~~- fO 

u. ^ o Sli 



2 E 

Q. Q h- 

O Q- 


Q 9 
b < 


i Q , 

O O - 

in or 


rS O z 

i ,82 



0.300 -0.2S 


















-. 6 



S- s 



<U D 

ti y 




Vol 48, No. 6 

;ter of the sprocket. H = C X /V/360 where C is the 
:he nearest quarter of a pitch length. 



4-l 5fl 

O g 

| | 


oj *o a 1 


ress as a decimal in the formulas.) 





















film thickness. 













if path is curved away from the sprocket. Minimum 

! path is curved toward the sprocket. Minimum RZ = 

z s 











*^ V 

K . 


.o*5b S 




ii >> 

4) 42 



^3 a) 





5 3 
> i 

%_> J3 V 
a aJ w 

% *u 







CT3 <U 




^ fe 

<L> *r? 








Number of teeth on one end of sprocket. 

Number of film pitch lengths in direct contact 
corresponding angle of contact in degrees. 
H can be obtained by observation, but should 

Number of film pitch lengths between the int 
F = E X TV/360 where E is the correspond 
F can be obtained by observation, but should 

Per cent maximum film shrinkage to be accom 

Per cent minimum film shrinkage to be accom 
considered, treat it as negative shrinkage. 

Maximum thickness of tooth in inches at root 
Minimum permissible tooth thickness is contr 











Diameter in inches of the surface 3n which th 
surface.) The tolerance for D equals the t( 

Minimum radius of film path entering or leav 
Ri = V4 inch. 

Minimum radius of film path entering or leavii 
0.7 D. 

Radius of tooth. 
Distance from root diameter (D) to center for 




June 1947 



&$f ft *&.S3ae.i::lg| 


& +j ^ H en -^ ^ > O cy-g^ 2 53 | 

sa's'c . 1J * 2 3 j o 's"^ <a . *,. 



JH rt ro ^^ ^ ^^ 0^3 
fS u* ft! J2^5-S^ 




6 o rt ^ o 


&T3 rt o 




all^-M-f-a S S 





ft o to So OT s., 



. bO y 



8S S o S o T 


for the specific dimensions given in the original standards might afford 
the designer a more flexible means of meeting the requirements of each 
particular application. The Chairman of the Committee on Stand- 
ards appointed a subcommittee to prepare new standards. It is at 
the instigation of that subcommittee that these proposals are being 
submitted to the Society for comment and criticism. 

Much of the delay in presenting this paper and the standards to the 
Society has been caused by investigation of several new and interest- 
ing aspects of the operation and design of sprockets. These have been 
examined by members of several departments of the Eastman Kodak 
Company, and the results are reflected in this paper. We hope that 
presentation of these aspects will result in the preparation of addi- 
tional papers in the future. 

Fig. 1 is the proposed standard for 16-mm sprockets. It is divided 
into four sections: illustrations, formulas and examples, nomencla- 
ture, and appendix. As explained above and in the Appendix, the 
standard was developed to give the designing engineer an opportunity 
to specify sprocket dimensions for specific applications and condi- 

Provision has been made for camera, printer, and projector sprock- 
ets having any practicable number of teeth. Particular attention 
has been given to the shape of the film path and to the lateral profile 
of the sprocket itself and also of guides, rollers, and film gates. 

Variations of Film. The one element in motion picture equipment 
to which practically all other elements must be referred dimension- 
ally is the film. Unfortunately, because of requirements of thick- 
ness, flexibility, and transparency, this is made of materials which 
are subject to dimensional variation. Improvements in film bases 
during recent years have increased the stability of the film appre- 
ciably, but some variation will probably exist as long as the use 
of transparent film continues. 

Because of the variation of the film, the sprocket, which has the 
most involved contact with the film of any of the mechanical ele- 
ments, has been the subject of more attempts at standardization than 
any other part. This present analysis of the film-to-sprocket func- 
tion may not be the end-all or the cure-all, but it introduces some fac- 
tors that are new or are at least treated differently than in previous 

Of the several kinds of variation of the film, shrinkage has the most 
effect on the rest of the system. Raw film is slit and perforated with 

June 1947 



extreme accuracy, but under various conditions of treatment, aging, 
and humidity, shrinkage up to one per cent, or sometimes more, may 
occur. The processing of exposed film may cause variation, and con- 
ditions of storage make the dimensions that apply when the strip is 
run through the apparatus most unpredictable. 

Accommodation for these changes in film caused by shrinkage is 
the principal factor in the design of sprockets. There are two reasons, 
varying in relative importance according to the function of the ma- 
chine of which the sprocket is a part, why this accommodation is 
necessary. The first is the wear of the film by the' sprocket, which is 
important in projection equipment in which the same film may be run 


FIG. 2. 

many times. Continued satisfactory operation depends as much or 
more upon the maintenance of accurate, undamaged perforations as 
upon the condition of the elements in contact with or adjacent to the 
sound and picture areas. The second reason for specifying the opti- 
mum relation between the film and the sprocket applies to sound and 
printing sprockets. Here the primary requisite is to run the film at a 
relatively constant velocity in order to ensure freedom from flutter. 
Fortunately, these two conditions, freedom from wear and freedom 
from flutter, are not in opposition to each other, and it is possible to 
design for usable results in both respects. 

There are three aspects of sprocket design for which the potential 
shrinkage of the film must be taken into account. They are determi- 
nation of (7) the circular pitch of the teeth, (2) the shape and thick- 
ness of the teeth, and (3) the lateral profile of the sprocket. They 



Vol 48, No. 6 

are considered separately in the three sections of this report that fol- 
low, but ultimately they are interrelated. 


Function of Sprockets. Let us consider first the conditions under 
which sprockets in motion picture equipment operate. Essentially 
their purpose is to co-ordinate the movement of film through the 



FIG. 3. 

equipment so that all functions are kept in their proper relation. 
Usually they act as a buffer between film under tension on one side 
of the sprocket and film in a free condition on the other. Occasion- 
ally the film is under tension on both sides, but even in this case the 
tension on one side is almost always greater than that on the other . 
Thus, the effective condition is the same. 

June 1947 16- AND 8-MM SPROCKET STANDARDS 491 

Path of the Film. The path of the film as it passes over the 
sprocket is governed by the relative positions of the adjacent ele- 
ments in the system, such as the supply reel and the gate. This path, 
however, is usually modified by rollers or guides near the sprocket. 
From the point where this film path intersects the path of the tip of 
the sprocket teeth until it passes beyond the similar intersection on 
the other side of the sprocket there is a zone of action on which the 
design of the sprocket is based. This zone of action, which can be 
measured and called the "arc of engagement," Fig. 2, contains a 
smaller "arc of contact" through which the film is in contact with the 
root diameter of the sprocket. This is usually a part of the sprocket, 
but it may be a separate guiding surface. 

For simplicity of illustration, the film is shown in Fig. 2 entering 
and leaving the sprocket in straight lines tangent to the root diameter, 
but by far the more usual path is a curve, either away from the 
sprocket as shown in Fig. 3 (a) or toward the sprocket as in 3(b). Or, 
the film can approach the sprocket in a path of one shape and leave 
in a different curve. It is necessary to establish limits for the mini- 
mum radius of curvature toward and away from the sprocket. This 
must be done on the basis of experience rather than on definite engi- 
neering considerations. Film curving away from the sprocket makes a 
reverse bend, which shortens the life of splices. Also, film left 
threaded in a camera, particularly during changes in climatic condi- 
tions, may take a set which will disturb its proper movement through 
the rest of the system. In view of these factors, a minimum radius of 
one-quarter inch is proposed for R if the radius of the path that curves 
away from the sprocket. 

The minimum radius of curvature toward the sprocket is governed 
by more definite factors. Obviously it cannot be less than the radius 
of the sprocket. A sprocket of one-quarter-inch radius, the smallest 
radius advisable for any point in the path, would have only five teeth 
and is too small to be recommended. Curvature of the film toward 
the sprocket does not involve reverse curvature of the film and there- 
fore does not affect the life of splices. But film curvature in this direc- 
tion that too closely approaches the radius of the sprocket increases 
the arc of engagement so much that the tooth becomes very thin and 
its shape is affected adversely. The proposed value of 0.7D for ^2, 
the minimum radius when the film is curved toward the sprocket, is 
derived analytically in Section 2 of this paper. 

Types of Sprockets. In motion picture equipment there are two 



Vol 48, No. 6 

basic types of sprockets, differing in the relation between the direc- 
tion of the external tension on the film and the direction of the mo- 
tion. In the first 'case these directions are opposed, and the sprocket 
is a drive sprocket. Examples are the feed sprocket, which pulls 
the film from the supply reel, the intermittent sprocket, which pulls 
the film through the gate, and the sound sprocket, which pulls the 
film past the recording or reproducing aperture. The second case is 
the take-up or holdback sprocket. Here the external tension is in 
the direction of the motion, and the film is held back by the sprocket. 





FIG. 4. Drive sprocket (a); holdback sprocket (b). 

In addition, there is the combination sprocket. This is used in re- 
versible apparatus where the function of the sprocket changes as the 
direction of motion changes, while the direction of film tension remains 
the same. Also, in many cameras and in some projectors, one section 
of a single sprocket serves as a drive sprocket and another section as 
a holdback sprocket. Combination sprockets are not recommended 
for highly accurate apparatus such as printers or other professional 

Figs. 4(a) and 4(b) illustrate the two basic sprocket conditions, 
drive and holdback. 

June 1947 16- AND 8-MM SPROCKET STANDARDS 493 

The sprocket in Fig. 4 (a) is driving the film by the front or left- 
hand face of tooth A. As the sprocket rotates, tooth A leaves the 
film, which then slips backward so that the load is transferred to the 
front face of tooth B . Meanwhile, tooth D enters the perforation with- 
out touching the film, as it should if wear is to be kept to a minimum. 

Fig. 4(b) shows a properly designed sprocket for the holdback con- 
dition. In this case, the film is held back by the rear or left-hand face 
of tooth A i. As the tooth leaves, the film slips forward, the load is 
transferred from tooth A\ to tooth BI, and tooth DI freely enters the 
perforation that is coming into engagement. 

Examination shows that in Fig. 4 (a) the circular pitch of the 
sprocket teeth is greater than the pitch of the film, while in Fig. 4(b) 
the pitch of the sprocket teeth is less than the pitch of the film. From 
observation of the action under these two conditions, we can conclude 

(1) A properly designed drive sprocket should have a circular pitch 
equal to or greater than the pitch of the film; and 

(2) A properly designed holdback sprocket should have a circular 
pitch equal to or less than the pitch of the film. 

These conclusions are not novel but were evident in Jones' paper on 
Film Sprocket Design. 1 

Experimental Confirmation of Above Rules. There is some re- 
cent experimental evidence to support the statements made above. 
Films of three different shrinkages were run in succession on three 
sprockets having different pitches. Each of the nine combinations 
of film and sprocket was observed and photographed, under both 
drive and holdback conditions, with external tensions of 4, 6, 8, and 
10 oz applied to the film. 

Fig. 5 illustrates qualitatively the results of these tests. It shows, 
for both drive and holdback conditions, that when the shrinkage of 
the film and that of the sprocket differ in the theoretically correct 
direction, the operation is satisfactory. But when the shrinkage dif- 
ference is in the other direction, there is trouble. In the case of drive 
sprockets, no actual loss of loop occurred, but it is apparent in the 
pictures that violation of the theory results in a disturbance caused by 
contact between the entering tooth and the edge of the perforation. 
On holdback sprockets, since there was no sprocket clamp to prevent 
it, the film rose to the tops of the teeth, and the take-up device pulled 
the film ahead so that the loop at the other side of the sprocket was 



Vol 48, No. 6 




Film Longer than Sprocket 

Film Shorter than Sprocket 
































>l.6 +1.4 +1.2 

-<X2 -0,4 -06 -Ofl -1.0 -12 -1.4 -I 

/ = Slight interference at entering S = Satisfactory. 

tooth. D = Distortion near point of 

E = Extreme interference at enter- contact, 

ing tooth. 


Film Longer than Sprocket 

































Film Shorter than Sprocket 

+0.6 +0.4 +02 

-0.2 -0.4 -0.6 -OB 

6" = Satisfactory. / = Slight interference at enter - 

V = Slight vibration of film at leav- ing tooth. 

ing tooth may be due to F = Failure film leaves 
large amount of forward slip. sprocket and loop is lost. 

FIG. 5. 

June 1947 16- AND 8-MM SPROCKET STANDARDS 495 

lost. Increased tension aggravated these disturbances, but when the 
pitch differential was in the correct direction, an increase of tension 
made no perceptible difference. These are merely observations of 
the functioning of the sprocket, not wear tests of the type described 
by Vilbrandt. 2 In his test, he shows that the running life of the film is 
reduced when the external tension applied to the film is increased. 

Pitch of Sprocket in Relation to Thickness of Tooth. Interference 
of the film with the sprocket exists when there is so much difference 
between the pitch of the film and the pitch of the sprocket that 
there is contact between the sprocket teeth and the perforations at 
both ends of the arc of contact. Interference can occur at the 
outer edges of the teeth, as would happen if the film in Fig. 4(a) 
were shorter, or at the inner edges, as would result with longer film 
in Fig. 4(b). From the limiting conditions shown in Figs. 4(a) and 
4(b) can be derived primary equations for freedom from interference 
of this type. 

Drive sprocket HF + p = HP + T 

Holdback sprocket HF - p = HP - T 

H = integral number of film pitch lengths in the arc of contact 
F = length of one film pitch, in inches 

p = height of the perforations, in inches 

pitch of sprocket teeth on the pitch circle at the center of the film, in 

T = maximum thickness of the tooth at the root diameter, in inches. 

These formulas in approximately the same form were shown by 
Jones 1 as well as by Hill and Schaefer. 3 

It is evident from consideration of these equations that with F and 
p established for a given shrinkage of film, P can vary through a wide 
range if corresponding changes are made in T. The limit of this vari- 
ation is controlled by the limits for T, which cannot be greater than p 
nor less than zero. 

But there are conditions other than interference to consider. Figs. 
4 (a) and 4(b) illustrate that the direction of the slippage is governed